sdbusplus: use shorter type aliases

The sdbusplus headers provide shortened aliases for many types.
Switch to using them to provide better code clarity and shorter
lines.  Possible replacements are for:
  * bus_t
  * exception_t
  * manager_t
  * match_t
  * message_t
  * object_t
  * slot_t

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I8e2242adb79be342562c9b7f3d2153dfdf578085
diff --git a/softoff/softoff.hpp b/softoff/softoff.hpp
index 302144c..e9a8f44 100644
--- a/softoff/softoff.hpp
+++ b/softoff/softoff.hpp
@@ -24,7 +24,7 @@
      *  @param[in] bus       - system D-Bus handler
      *  @param[in] event     - sd_event handler
      */
-    SoftPowerOff(sdbusplus::bus::bus& bus, sd_event* event);
+    SoftPowerOff(sdbusplus::bus_t& bus, sd_event* event);
 
     /** @brief Is the pldm-softpoweroff has error.
      * if hasError is true, that means the pldm-softpoweroff failed to
@@ -82,7 +82,7 @@
      *
      *  @param[in] msg - Data associated with subscribed signal
      */
-    void hostSoftOffComplete(sdbusplus::message::message& msg);
+    void hostSoftOffComplete(sdbusplus::message_t& msg);
 
     /** @brief Start the timer.
      *
@@ -133,7 +133,7 @@
     bool VMMPdrExist = true;
 
     /* @brief sdbusplus handle */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
 
     /** @brief Reference to Timer object */
     phosphor::Timer timer;