disp: msm: dsi: DSI PHY V4 support of dynamic clock switch

This change adds support for dynamic switching of dsi clocks
to avoid RF interference issues. DSI PHY V4 support is added.

Change-Id: I5bdbd6d2916692087c0192d23c8e7598238f161f
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>
Signed-off-by: Yujun Zhang <yujunzhang@codeaurora.org>