alsa: reset watermark to initial values on resume

alsa: reset watermark to initial values on resume

Watermark level and latency values are not restored when
resuming, the values used prior to suspending are reused.
This leads to side effects when underruns happen and buffer
sizes are updated, PulseAudio can never meet lower latency
requirements.

Solution: keep track of watermark and latency values on sink or
source creation, and reapply them on resume to start with
a clean slate.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>