Fix trivial warnings hidden by -isystem

Fix the trivial warnings that are hidden by the use of -isystem to
include frameworks/av and caught by -Werror.

Test: m -j checkbuild
Bug: 31751828
Change-Id: I155f9f772ce0a84b364313814cb7cf528b9de4eb
diff --git a/media/libmediaplayerservice/nuplayer/RTSPSource.cpp b/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
index 9264e49..8b3d0dc 100644
--- a/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
+++ b/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
@@ -544,7 +544,7 @@
         return;
     }
 
-    CHECK_EQ(msg->what(), (int)kWhatNotify);
+    CHECK_EQ(msg->what(), kWhatNotify);
 
     int32_t what;
     CHECK(msg->findInt32("what", &what));