audio: Output latency update in Audio Track

AudioTrack needs to query latency from the output descriptor each
time it uses mAfLatency to calculate timestamp or return the track
latency. Until now, the output descriptor latency was queried and
stored when a track is created. On a device switch, IO descriptors
table saved in AudioSystem is updated to reflected the latest
latency values.  Unless a device switch lead to a track teardown,
AudioTrack will be unaware of the latest latency value. Therefore
explicitly check the latest mAfLatency value on each getTimeStamp
call.

Test: Podkicker 2.2x, Photos 240fps and BT
Bug: 35075600
authored-by: Aniket Kumar Lata <alata@codeaurora.org>
Change-Id: I06282182364703574a7d66d2b5cd1301679dfade