Fix trivial compiler warnings

Test: Compile & executed many of the tests on Marlin
Change-Id: I2d88922c5dcc88de0394c5bfade02ca1dd9d7b60
diff --git a/opengl/tests/gralloc/gralloc.cpp b/opengl/tests/gralloc/gralloc.cpp
index 8987040..29e0882 100644
--- a/opengl/tests/gralloc/gralloc.cpp
+++ b/opengl/tests/gralloc/gralloc.cpp
@@ -37,7 +37,7 @@
     return d;
 }
 
-int main(int argc, char** argv)
+int main(int /*argc*/, char** /*argv*/)
 {
     size_t size = 128*256*4;
     void* temp = malloc(size);