msm_fb: display: add overlay1 writeback enable and disable

This logic is used to enable mdp overlay1 writeback mode when
downscaling in any pipe for mixer1 requires a mdp clk rate more than
its max, and disable it when no pipe requires more than max mdp clk
rate.

CRs-fixed: 330895
Change-Id: I67632fdc2cf4c357753603fee293817bb87581ca
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>
3 files changed