msm: mdss: fix higher power consumption in ambient mode for 8909w

MDP3 clocks are active when ULP state is requested from fb_pm_suspend.
This was resulting in higher power consumption in ambient mode.

Fix the issue by turning off MDP3 clocks in control off
call for ULP power state.

Change-Id: Ia2fffa25928aa07d838d6fb5432a765d9721eb5a
Signed-off-by: Sachin Bhayare <sachin.bhayare@codeaurora.org>