Soc: msm: Synchronize access to LPA stream

 -Synchronize hw_ptr, appl_ptr access between the LPA
  driver and event handler and the ALSA core framework.

 -ported change from compressed driver
  change id I118bfdf4a866cde05d9ebcd21f756da209b69cc5

Change-Id: I0fe63d8fa4a5372b6c231a5ee44532140cce1301
CRs-Fixed: 511481

Signed-off-by: Preetam Singh Ranawat <apranawat@codeaurora.org>