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
Merged-In: I155f9f772ce0a84b364313814cb7cf528b9de4eb
(cherry picked from commit b8c35f94470d1518e2def0582aaec4e038c92af0)
diff --git a/media/libnbaio/include/NBLog.h b/media/libnbaio/include/NBLog.h
index 4e86d7c..bcebe9e 100644
--- a/media/libnbaio/include/NBLog.h
+++ b/media/libnbaio/include/NBLog.h
@@ -381,7 +381,7 @@
                                          String8 *timestamp,
                                          String8 *body);
     // dummy method for handling absent author entry
-    virtual size_t handleAuthor(const FormatEntry &fmtEntry, String8 *body) { return 0; }
+    virtual size_t handleAuthor(const FormatEntry& /*fmtEntry*/, String8* /*body*/) { return 0; }
 
     // Searches for the last entry of type <type> in the range [front, back)
     // back has to be entry-aligned. Returns nullptr if none enconuntered.