drm/msm/dsi-staging: config AB/IBB power when AOD mode enter/exit

ELVDD/ELVSS has a dip during AMODE panel AOD exit hand-off.
According to PMIC team's suggestion, need to config the AB/IBB
power to REGULATOR_MODE_IDLE/REGULATOR_MODE_NORMAL to fix the dips.

Change-Id: Ia5cbd4d698de262e02a660f670865c03dda1e04a
Signed-off-by: Yuan Zhao <yzhao@codeaurora.org>