msm: mdss: Make notify update waits interruptible

Wait for completion in notify update call are uninterruptible
causing excessive delay during suspend cases. Making them
interruptible.

Change-Id: I1a4ff6ce3e0add21d4e46a41372b076b277d10f5
Signed-off-by: Krishna Chaitanya Parimi <cparimi@codeaurora.org>