Enable clang-tidy in libaaudio.

Enabling clang-tidy could help find programming errors at compile time.

Bug: 186572209
Test: make, atest AAudioTests
Change-Id: If48282d10701df87b80a99e2a3d2199437189d70
diff --git a/media/libaaudio/src/flowgraph/SourceFloat.cpp b/media/libaaudio/src/flowgraph/SourceFloat.cpp
index 4bb674f..5b3a51e 100644
--- a/media/libaaudio/src/flowgraph/SourceFloat.cpp
+++ b/media/libaaudio/src/flowgraph/SourceFloat.cpp
@@ -25,7 +25,7 @@
         : AudioSource(channelCount) {
 }
 
-int32_t SourceFloat::onProcess(int64_t framePosition, int32_t numFrames) {
+int32_t SourceFloat::onProcess(int64_t /*framePosition*/, int32_t numFrames) {
 
     float *outputBuffer = output.getBlock();
     int32_t channelCount = output.getSamplesPerFrame();