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/requester/mctp_endpoint_discovery.cpp b/requester/mctp_endpoint_discovery.cpp
index b95935f..d13c979 100644
--- a/requester/mctp_endpoint_discovery.cpp
+++ b/requester/mctp_endpoint_discovery.cpp
@@ -14,7 +14,7 @@
 namespace pldm
 {
 
-MctpDiscovery::MctpDiscovery(sdbusplus::bus::bus& bus,
+MctpDiscovery::MctpDiscovery(sdbusplus::bus_t& bus,
                              fw_update::Manager* fwManager) :
     bus(bus),
     fwManager(fwManager),
@@ -68,7 +68,7 @@
     }
 }
 
-void MctpDiscovery::dicoverEndpoints(sdbusplus::message::message& msg)
+void MctpDiscovery::dicoverEndpoints(sdbusplus::message_t& msg)
 {
     constexpr std::string_view mctpEndpointIntfName{
         "xyz.openbmc_project.MCTP.Endpoint"};