audio: update switch to use FALLTHROUGH_INTENDED

Test: compile, sanity
Bug: 117509050
Change-Id: I1394e22621af6519b6679353f31f06561ffeacad
Merged-In: I1394e22621af6519b6679353f31f06561ffeacad
(cherry picked from commit 74213cb95cce829cc2e7534a9572f1236709b5fe)
2 files changed