sdbusplus: avoid deprecated phosphor::Timer

sdbusplus had an older type named `phosphor::Timer` which was
recently renamed to `sdbusplus::Timer`.  Update the code to use
the new type alias.

Change-Id: I68d3968bcb359bee5ea0c9e695572b68fcf34136
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/softoff/softoff.hpp b/softoff/softoff.hpp
index fce0a52..2bf3968 100644
--- a/softoff/softoff.hpp
+++ b/softoff/softoff.hpp
@@ -135,7 +135,7 @@
     sdbusplus::bus_t& bus;
 
     /** @brief Reference to Timer object */
-    phosphor::Timer timer;
+    sdbusplus::Timer timer;
 
     /** @brief Used to subscribe to dbus pldm StateSensorEvent signal
      * When the host soft off is complete, it sends an platform event message