ARM: dts: msm: disable display nodes for sdm670 RUMI

Display is not modelled on sdm670 RUMI. So disable all
display related nodes for the same.

Change-Id: Ide47c499e8136a5c9661288fcb58b2233346643b
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>