ARM: dts: msm: vote for CX regulator to prevent vddmin

With smart panels, command mode display panels, during static screen, soc
can be put into low power mode. This low power mode puts soc into vddmin
but with vddmin, DSI lanes observe spurious disturbance and can result
into corruption. To prevent vddmin, vote for CX regulator from display
driver if smart panel and static screen.

Change-Id: I8aeefd3bd6be3a68ed63631d7d7f71b143e50f53
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>