ARM: dts: msm: include supported panels for msm8974

Include all the supported panels for msm8974 in a
separate devicetree file which enables
access to all the supported panel nodes from
dsi controller. This allows implementation
of panel detection.

Change-Id: I6b7fd89652dff1858caa1f45d883170d5a3f2278
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>