msm: mdss: fix issues related to transitions in and out of doze mode

When entering doze mode, ensure that the tear-check setup is not
torn down. In addition, do not disable the split-display configuration.
This is to ensure that mdss driver can continue to handle any display
updates in doze mode. Similarly, when transitioning from doze power
state to blank power state, ensure that we do not send panel unblank and
panel on events. These events should only be sent when transitioning to
unblank power state.

Change-Id: If5ca1cdd20bb442e773912575c0a6e204c0ca1a2
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>