AudioSessionOut: Fix to handle a single write() with an empty buffer

- This fix is a workaround to exit cleanly in the case where the AudioSink
  write might give just a single zero length buffer to the driver.

Change-Id: I68d023e6f0bd5b5e4f593a42b26c685e3405288b
CRs-Fixed: 445182
Merge "AudioSessionOut: Fix to handle a single write() with an empty buffer" into cm-10.1
alsa-sound: Adjustment for tunnel mode buffer size

- Make necessary adjustments to align the buffer size
  for tunnel mode playback to satisfy the following condition
- Buffer size is a multiple of LCM(1,2,4,6,8)
- Buffer size is aligned to 4k.
CRs-Fixed: 447274, 442365

Change-Id: Ieb188cba6945b96e99bad4ceba4b53112383fd57
Merge remote-tracking branch 'upstream/cm-10.1' into cm-10.1