msm: mdss: Cancel ESD workqueue whenever display off happens

Display can be turned off by using different ioctls. Make sure that
in all the cases ESD workqueue is cancelled.

CRs-Fixed: 626835
Change-Id: Id14992665e4a86941386a8269600d322c3500a70
Signed-off-by: Shivaraj Shetty <shivaraj@codeaurora.org>