ASoC: msm: lock read/write when add/free audio ion memory

As read/write get access to ion memory region as well, it's
necessary to lock them when ion memory is about to be added/freed
to avoid racing cases.

CRs-Fixed: 1071809
Change-Id: I436ead23c93384961b38ca99b9312a40c50ad03a
Signed-off-by: Walter Yang <yandongy@codeaurora.org>