msm:mdss: Fix the issue with AD resume

AD is not configured correctly on dual DSI devices during
suspend/resume. The AD configuration data from user space are
only copied to the master AD configuration structure, and the AD
configuration structure attached to the right mixer (slave AD structure)
is never filled. So in the resume function, we cannot use the AD
configuration data from the slave AD configuration. Use the one
from the master structure instead.

Change-Id: I04cf3c467c2614420e01f9177f564eec7ce7bb23
Signed-off-by: Ping Li <quicpingli@codeaurora.org>