msm: mdss: force revalidate layers after resolution switch

Avoid skipping validation for all layers during ATOMIC_COMMIT
validate call after dynamic resolution switching. Though the
configs remain the same for few layers, revalidation is required
based on the new resolution as the src_split and other settings
might have changed.

Change-Id: I3f1f2e09c90e8ff1a6380e35ed9e980b5c2be46c
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>