msm: mdss: reset runtime status upon device resume

MDSS is power-collapsed in idle screen cases using the pm runtime
framework. However, it is possible that the runtime PM status may
not match with the post-system sleep status when the device is
resumed. This sometimes leads to the inconsistencies in MDSS
idle-power collapse upon system resume. To address this issue,
reset the runtime PM status in the pm resume handler.

Change-Id: I5696ce6c154f2898b82e70119d3d9a2be79b59b7
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>