fix compiler warnings

Fix a couple unused-parameter warnings so we can turn the warnings all
the way up.

Change-Id: I36c611da5a10732dbb89e289e42a870c902dd245
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/mmc/activation_mmc.cpp b/mmc/activation_mmc.cpp
index 84a1e98..b5a5669 100644
--- a/mmc/activation_mmc.cpp
+++ b/mmc/activation_mmc.cpp
@@ -16,7 +16,7 @@
 void ActivationMMC::startActivation()
 {}
 
-void ActivationMMC::unitStateChange(sdbusplus::message::message& msg)
+void ActivationMMC::unitStateChange(sdbusplus::message::message&)
 {}
 
 void ActivationMMC::finishActivation()