msm: mdss: Set low framerate on ambient mode

set FRAMERATE_CTRL, as low as setting on dts,
to reduce the power consumption on the ambient mode
this will set 50Hz for Idle mode, and full colors partial mode.

Change-Id: I133a614b5b7383b1be9eaac62b1f090bc17b243e
Signed-off-by: Se Hun Kim <sean2.kim@lge.com>