clang-tidy: Enable readability-convert-member-functions-to-static

This check finds non-static member functions that can be made
static because the functions don’t use this.
This check also triggers readability-static-accessed-through
-instance check as we are trying to access a static member
function through an instance.

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I6efe76666f75fb4f65621796466d9347cea25d01
diff --git a/manager/manager.hpp b/manager/manager.hpp
index ea37798..0177241 100644
--- a/manager/manager.hpp
+++ b/manager/manager.hpp
@@ -130,8 +130,9 @@
      *
      *  @return:              -  0: success, -1: LED set failed
      */
-    int drivePhysicalLED(const std::string& objPath, Layout::Action action,
-                         uint8_t dutyOn, const uint16_t period);
+    static int drivePhysicalLED(const std::string& objPath,
+                                Layout::Action action, uint8_t dutyOn,
+                                const uint16_t period);
 
     /** @brief Set lamp test callback when enabled lamp test.
      *
@@ -148,9 +149,6 @@
     /** Map of physical LED path to service name */
     std::unordered_map<std::string, std::string> phyLeds{};
 
-    /** DBusHandler class handles the D-Bus operations */
-    DBusHandler dBusHandler;
-
     /** @brief Pointers to groups that are in asserted state */
     std::set<const Layout::GroupLayout*> assertedGroups;