msm: mdss: remove surface pipe locks

Pipe locks are used to prevent pipes being updated by two different
threads, and to avoid updates when pipes are being released.
Update by two different threads are already protected by a different
lock (mfd->ov_lock). For updated while being released replace the usage
of pipe locks with ref counts to ensure pipe is freed only until there
are no updates going on.

CRs-Fixed: 438108
Change-Id: I5c41b4efa8d42bfcfc1b9e6ebe4225c46bd27084
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>
4 files changed