ALSA: pcm: add locks for accessing runtime resource

Add spin lock to resolve race conditions while
accessing substream runtime resource.

CRs-fixed: 2112713
Change-Id: I8db743303ceb50205d62adfc02caf6ecab635d47
Signed-off-by: Karthikeyan Mani <kmani@codeaurora.org>
Signed-off-by: Meng Wang <mengw@codeaurora.org>