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: Ibd2a0b512bfb7caf65bfab64b271d194da520aac
diff --git a/softoff/softoff.cpp b/softoff/softoff.cpp
index e6ed0eb..333d4d7 100644
--- a/softoff/softoff.cpp
+++ b/softoff/softoff.cpp
@@ -53,7 +53,7 @@
 }
 
 // Function called on host control signals
-void SoftPowerOff::hostControlEvent(sdbusplus::message::message& msg)
+void SoftPowerOff::hostControlEvent(sdbusplus::message_t& msg)
 {
     std::string cmdCompleted{};
     std::string cmdStatus{};