dt-bindings: msm: Add following properties to control POMS

- qcom,mdss-dsi-panel-mode-switch to enable panel operating mode switch.
- qcom,mdss-dsi-video-mode to indicate current timing mode can only
support video mode.
- qcom,mdss-dsi-cmd-mode to indicate current timing mode can only
support command mode.

Change-Id: I0e559a921ed6a59deab3aeb805d2aa70acf75b4a