audio: add watchdog on buffer full condition

There have been several reports of devices losing audio
completely until rebooted.
The logs showed that the kernel buffer was steadily full
as if playback did not start or stopped and did not restart.

This change adds a watchdog to restart media server in case such
a condition persists.

Also add more log in case of errors reported by tinyalsa.

Bug 6699340.

Change-Id: Ie3e1565e1c1e6fd8581e6969343d481a63d5c880
1 file changed