NuPlayerDriver: Maintain the timeStamp after seek

 While offload playback is going on, if user pause
 and seeks to new position before offload tear-down,
 on resume playback starts from old time-stamp.

 Once tear-down happens NuPlayer loses updated time-stamp
 so while resuming it resumes playback with stale time-stamp.
 Make sure the updated time-stamp is maintained in
 NuPlayerDriver which is used while starting the playback
 after resume.

authored-by: Sharad Sangle <assangle@codeaurora.org>
Change-Id: Ie125cf0fab1b0a237e67e43b0e5b4a704483ef99