ARM: dts: msm: add sim cmd/vid panel support for msmskunk

Add command mode and video mode simulator panel support
for msmskunk target. The patch also adds the panel
documentation which is missing on the 4.9 kernel
branch.

Change-Id: I074ba273bf533b9037eba7c1174f3102fbdcfa88
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>