drm/msm/dsi-staging: enable frame MISR on DSI

Add misr_data debugfs node under DSI panel node and connect
it to respective frame MISR control registers for command and
video modes. Since in command mode, the DSI control is powered
down between frames, the MISR data is cached in local context.

Change-Id: I9fb292b1f8cfc0ec15cbfb4d221394166e15bcf7
Signed-off-by: Rajkumar Subbiah <rsubbia@codeaurora.org>