ARM: dts: msm: make cmd mode as default display for SDM845

Make dual dsi command mode as default display on SDM845 CDP and MTP.
Add respective backlight settings, GPIO settings to support
this display.

Change-Id: Ic0adea3a4aa2452c59facdb476cf963745788635
Signed-off-by: Shashank Babu Chinta Venkata <sbchin@codeaurora.org>