msm: mdss: fix fence time out issue in MDP3 driver

MDP3 ioctls were not synchronized. This resulted early return from blocking
ioctls which resulted in use of incorrect timeline value for mdp_fence and
resulted in fence deadlock. As driver end up sending far in future timeline
value to its client.

Fix issue by using MDP_NOTIFY_FRAME_CTX_DONE event for synchronizing ioctls.

Change-Id: Ie0809e53e29c684071c4003ee75267793e8dd3b7
Signed-off-by: Sachin Bhayare <sachin.bhayare@codeaurora.org>