ALSA: pcm: use lock to protect substream runtime resource

Use a spinlock to protect runtime resource in substream
against race conditions which may lead to use-after-free.

CRs-fixed: 2112713
Change-Id: I37dee68cad5eae05b21cfade3dabc0c2b79be6b8
Signed-off-by: Karthikeyan Mani <kmani@codeaurora.org>
Signed-off-by: Meng Wang <mwang@codeaurora.org>