drm/msm/sde: enable lm misr after frame trigger

Perform MISR enable after frame trigger and then collect misr after
status bit is set. Previously misr was enabled through debugfs, so if
system goes into idle power collapse before commit, then misr enable
status was not retained. Also it was not waiting for misr status bit.

Change-Id: Ifc3030c08c3e43e0bd58e81ce15208c1938c76a2
Signed-off-by: Gurpreet Singh Dhami <gdhami@codeaurora.org>