msm_fb: display: add mdp blt mode and switch control

Switching mdp blt mode is done in isr or by turning on/off timing
generator. Add other options: by polling, always-on or always-off. And
add support for external dtv blt mode.

CRs-fixed: 390953
Change-Id: I5e9f52fc459a34cc99a0f71c04b8320edd821ff8
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>
4 files changed