msm: mdss: modify MDSS idle power collapse exit sequence

When MDSS is idle power-collapsed, any events that require hardware
programming should result in exiting idle power collapse. Currently,
this is only done whenever a screen udpate happens. However, it is
possible that other APIs may be called prior to the actual screen
update. To address these cases, add the exit sequence call at the
interface level as well.

Change-Id: I162e1c1c4137a2ba20ed0b76f0c182c2c931cc87
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>