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.hpp b/softoff/softoff.hpp
index bf3fbdd..23ff5db 100644
--- a/softoff/softoff.hpp
+++ b/softoff/softoff.hpp
@@ -35,8 +35,7 @@
      *  @param[in] event     - sd_event handler
      *  @param[in] objPath   - The Dbus path hosting SoftPowerOff function
      */
-    SoftPowerOff(sdbusplus::bus::bus& bus, sd_event* event,
-                 const char* objPath) :
+    SoftPowerOff(sdbusplus::bus_t& bus, sd_event* event, const char* objPath) :
         SoftPowerOffInherit(bus, objPath,
                             SoftPowerOffInherit::action::defer_emit),
         bus(bus), timer(event),
@@ -99,7 +98,7 @@
     static constexpr auto HOST_IPMI_INTF = "org.openbmc.HostIpmi";
 
     /* @brief sdbusplus handle */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
 
     /** @brief Reference to Timer object */
     Timer timer;
@@ -139,7 +138,7 @@
      * @param[in]  msg       - Data associated with subscribed signal
      *
      */
-    void hostControlEvent(sdbusplus::message::message& msg);
+    void hostControlEvent(sdbusplus::message_t& msg);
 };
 } // namespace ipmi
 } // namespace phosphor