Display pipe underrun counters in dumpsys

The normal mixer writes it's submix to a pipe, which is read by the fast
mixer.  Now dumpsys media.audio_flinger display the raw underrun counters
when fast mixer tries to pull from the pipe but doesn't get enough frames.

Change-Id: I72505f149f9e12802784da654a651d43734e1c79
2 files changed