msm: mdss: call suspend and resume panel events during runtime triggers

Send a panel suspend/resume event to all the MDSS devices to ensure
proper handling of regulators and clocks during the suspend/resume
sequence.

Change-Id: I820f5e4113f599ba53d4fa4726e406f74872f95f
Signed-off-by: Sree Sesha Aravind Vadrevu <svadrevu@codeaurora.org>