msm: mdss: fix deadlock between display and ESD check thread

Display thread holds ov_lock followed by mutex, while the ESD
check thread for cmd mode panel holds mutex followed by ov_lock.
Fix this deadlock by acquiring mutex before ov_lock in ESD check
thread.

Change-Id: I857f780e14a6ccb679e89ff16b19706d205df4b6
Signed-off-by: Ray Zhang <rayz@codeaurora.org>