Remove bogus compiler flag from libart-compiler.

Change-Id: I2e2c555cb80c745e3d9859b88f16491ea146b38f
diff --git a/compiler/Android.mk b/compiler/Android.mk
index 3edd913..2d38629 100644
--- a/compiler/Android.mk
+++ b/compiler/Android.mk
@@ -233,9 +233,6 @@
     endif
   endif
 
-  # TODO: clean up the compilers and remove this.
-  LOCAL_CFLAGS += -Wno-unused-parameter
-
   ifeq ($(ART_USE_PORTABLE_COMPILER),true)
     LOCAL_SHARED_LIBRARIES += libLLVM
     LOCAL_CFLAGS += -DART_USE_PORTABLE_COMPILER=1