msm: mdss: Allow CMD panels for Assertive Display

Remove the check that prevented command mode panels from enabling assertive
display functionality.

Change-Id: Iecf0f518a45da556d1d9d0558a7d2dc572cc82da
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>
Signed-off-by: Ping Li <quicpingli@codeaurora.org>
msm: mdss: Don't calculate AD with zero backlight

Don't calculate AD strength when backlight is zero to prevent updates that
would not be visible from impacting screen when first backlight request
arrives.

Change-Id: Iabf10317ef40ae7bd940d94297a62975947c5ee4
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>