msm: mdss: Move mutex lock outside esd status check

Release the mutex immediatly after wait for dma done,
this change will make sure there is no wait for commit
thread while esd status check is in progress.

Change-Id: I56a9c0f19d9b026159f1588b32dfd66de74e3020
Signed-off-by: Raghavendra Ambadas <rambad@codeaurora.org>