Avoid jumps to faulty position after seeks

When seeking multiple times it is possible that some seeks
are discarded in AwesomePlayer, which causes unwanted jumps
to faulty positions.
The reason is that a seek flag is reset twice in AwesomePlayer.
At first when the video seek is completed and then again when the
audio seek is completed. If a new seek is made after the previous
video seek completed but before the previous audio seek completed,
the new seek position is discarded by the previous audio seek
completion.

This fix makes sure that the seek flag is reset only when video
has completed the seek.

Change-Id: I8f8741d4cb8682345f1d1855bbad57c05f4e3c8d
AudioMixer: Remove tracks from enabledTracks after reseting outTemp

If any track goes through AudioMixer::process__genericNoResampling, and
its getnextbuffer returns NULL, Then that track is removed by AudioMixer
from enabledTracks.

Thus if all tracks getnextbuffer return NULL, Then this function doesn't
reset outTemp and last buffer in AudioFlinger's mMixBuffer will be
repeated and noise is observed.

Remove tracks from enabledTracks after reseting outTemp to zero, so that
process__genericNoResampling will reset outTemp and noise won't appear.

Bug: 12450065
Change-Id: I1ccac7ee4a3bf7fd930254356c072099e11e7c19
Signed-off-by: Gaurav Kumar <gaurav.kumar@broadcom.com>
Signed-off-by: Pierre Couillaud <pierre@broadcom.com>
Merge remote-tracking branch 'cm/cm-11.0' into HEAD