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>
msm: mdss: refactor command mode vsync control logic

Current logic is prone to corner case when mdss_mdp_remove_vsync_handler
is called twice: once from mdss_mdp_cmd_stop and again from vsync ctrl
logic. Need to properly identify the second call and avoid resetting the
rdptr ticks which prevent from clocks being turned off properly.

Change-Id: I9eeebd0c16e67a249508980427c81fa2e339edec
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>