Suppress implicit-fallthrough warnings in audioflinger etc.

Add FALLTHROUGH_INTENDED for clang compiler.

Bug: 112564944
Test: build with global -Wimplicit-fallthrough.
Change-Id: I8875bc7ed073aae84d5df97eb39c8c745ca627ef
diff --git a/services/audioflinger/Effects.cpp b/services/audioflinger/Effects.cpp
index a44b758..b3f5efd 100644
--- a/services/audioflinger/Effects.cpp
+++ b/services/audioflinger/Effects.cpp
@@ -248,7 +248,7 @@
     switch (mState) {
     case RESTART:
         reset_l();
-        // FALL THROUGH
+        FALLTHROUGH_INTENDED;
 
     case STARTING:
         // clear auxiliary effect input buffer for next accumulation