msm: mdss: Prevent non-zero backlight following display blank
msm: mdss: Prevent non-zero backlight following display blank

Force the backlight to zero before entering powerdown state to prevent
backlight from staying on during blank/suspend.

Change-Id: I2a078833c414d6b51d4e6eb64fd37b616164948a
Signed-off-by: Carl Vanderlip <c1ee614365181d9b29d91b6c5237384ed28bec62@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas