Fix cppcheck warnings

Warning message:
```
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/unique_ptr.h:97:16: error: invalid application of 'sizeof' to an incomplete type 'phosphor::led::fru::fault::monitor::Remove'
   97 |         static_assert(sizeof(_Tp)>0,
      |                       ^~~~~~~~~~~
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/unique_ptr.h:404:4: note: in instantiation of member function 'std::default_delete<phosphor::led::fru::fault::monitor::Remove>::operator()' requested here
  404 |           get_deleter()(std::move(__ptr));
      |           ^
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/stl_construct.h:88:15: note: in instantiation of member function 'std::unique_ptr<phosphor::led::fru::fault::monitor::Remove>::~unique_ptr' requested here
   88 |         __location->~_Tp();
      |                      ^
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/stl_construct.h:149:12: note: in instantiation of function template specialization 'std::destroy_at<std::unique_ptr<phosphor::led::fru::fault::monitor::Remove>>' requested here
  149 |       std::destroy_at(__pointer);
      |            ^
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/stl_construct.h:163:11: note: in instantiation of function template specialization 'std::_Destroy<std::unique_ptr<phosphor::led::fru::fault::monitor::Remove>>' requested here
  163 |             std::_Destroy(std::__addressof(*__first));
      |                  ^
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/stl_construct.h:193:35: note: in instantiation of function template specialization 'std::_Destroy_aux<false>::__destroy<std::unique_ptr<phosphor::led::fru::fault::monitor::Remove> *>' requested here
  193 |         return std::_Destroy_aux<false>::__destroy(__first, __last);
      |                                          ^
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/alloc_traits.h:948:12: note: in instantiation of function template specialization 'std::_Destroy<std::unique_ptr<phosphor::led::fru::fault::monitor::Remove> *>' requested here
  948 |       std::_Destroy(__first, __last);
      |            ^
/usr/lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/stl_vector.h:735:7: note: in instantiation of function template specialization 'std::_Destroy<std::unique_ptr<phosphor::led::fru::fault::monitor::Remove> *, std::unique_ptr<phosphor::led::fru::fault::monitor::Remove>>' requested here
  735 |         std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
      |              ^
../../../fault-monitor/fru-fault-monitor.hpp:48:14: note: in instantiation of member function 'std::vector<std::unique_ptr<phosphor::led::fru::fault::monitor::Remove>>::~vector' requested here
   48 |     explicit Add(sdbusplus::bus_t& bus) :
      |              ^
../../../fault-monitor/fru-fault-monitor.hpp:28:7: note: forward declaration of 'phosphor::led::fru::fault::monitor::Remove'
   28 | class Remove;
      |       ^
```

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I5c20a0031deff51e6bacccdd81310e95f14e52a0
diff --git a/fault-monitor/fru-fault-monitor.hpp b/fault-monitor/fru-fault-monitor.hpp
index 028e873..e5ddc53 100644
--- a/fault-monitor/fru-fault-monitor.hpp
+++ b/fault-monitor/fru-fault-monitor.hpp
@@ -25,54 +25,6 @@
  */
 void action(sdbusplus::bus_t& bus, const std::string& path, bool assert);
 
-class Remove;
-
-/** @class Add
- *  @brief Implementation of LED handling during FRU fault
- *  @details This implements methods for watching for a FRU fault
- *  being logged to assert the corresponding LED
- */
-class Add
-{
-  public:
-    Add() = delete;
-    ~Add() = default;
-    Add(const Add&) = delete;
-    Add& operator=(const Add&) = delete;
-    Add(Add&&) = default;
-    Add& operator=(Add&&) = default;
-
-    /** @brief constructs Add a watch for FRU faults.
-     *  @param[in] bus -  The Dbus bus object
-     */
-    explicit Add(sdbusplus::bus_t& bus) :
-        matchCreated(
-            bus,
-            sdbusplus::bus::match::rules::interfacesAdded() +
-                sdbusplus::bus::match::rules::path_namespace(
-                    "/xyz/openbmc_project/logging"),
-            std::bind(std::mem_fn(&Add::created), this, std::placeholders::_1))
-    {
-        processExistingCallouts(bus);
-    }
-
-  private:
-    /** @brief sdbusplus signal match for fault created */
-    sdbusplus::bus::match_t matchCreated;
-
-    std::vector<std::unique_ptr<Remove>> removeWatches;
-
-    /** @brief Callback function for fru fault created
-     *  @param[in] msg       - Data associated with subscribed signal
-     */
-    void created(sdbusplus::message_t& msg);
-
-    /** @brief This function process all callouts at application start
-     *  @param[in] bus - The Dbus bus object
-     */
-    void processExistingCallouts(sdbusplus::bus_t& bus);
-};
-
 /** @class Remove
  *  @brief Implementation of LED handling after resolution of FRU fault
  *  @details Implement methods for watching the resolution of FRU faults
@@ -127,6 +79,52 @@
         return matchStmt;
     }
 };
+
+/** @class Add
+ *  @brief Implementation of LED handling during FRU fault
+ *  @details This implements methods for watching for a FRU fault
+ *  being logged to assert the corresponding LED
+ */
+class Add
+{
+  public:
+    Add() = delete;
+    ~Add() = default;
+    Add(const Add&) = delete;
+    Add& operator=(const Add&) = delete;
+    Add(Add&&) = default;
+    Add& operator=(Add&&) = default;
+
+    /** @brief constructs Add a watch for FRU faults.
+     *  @param[in] bus -  The Dbus bus object
+     */
+    explicit Add(sdbusplus::bus_t& bus) :
+        matchCreated(
+            bus,
+            sdbusplus::bus::match::rules::interfacesAdded() +
+                sdbusplus::bus::match::rules::path_namespace(
+                    "/xyz/openbmc_project/logging"),
+            std::bind(std::mem_fn(&Add::created), this, std::placeholders::_1))
+    {
+        processExistingCallouts(bus);
+    }
+
+  private:
+    /** @brief sdbusplus signal match for fault created */
+    sdbusplus::bus::match_t matchCreated;
+
+    std::vector<std::unique_ptr<Remove>> removeWatches;
+
+    /** @brief Callback function for fru fault created
+     *  @param[in] msg       - Data associated with subscribed signal
+     */
+    void created(sdbusplus::message_t& msg);
+
+    /** @brief This function process all callouts at application start
+     *  @param[in] bus - The Dbus bus object
+     */
+    void processExistingCallouts(sdbusplus::bus_t& bus);
+};
 } // namespace monitor
 } // namespace fault
 } // namespace fru