drm/msm/dsi-staging: enable panel switching

Update panel properties using configuration file that can
be provided as a firmware. Use this configuration file if
it exists otherwise use panel properties from device tree.

Change-Id: Ie25fc74112397556c05b1fe8200a3ff9acd2a442
Signed-off-by: Samantha Tran <samtran@codeaurora.org>