ARM: dts: msm: enable support for NT35590 720p panel for msm8939

Add necessary DT entries to enable NT35590 720p video mode and
command mode panels on 8939 CDP. Also add support for backlight
and continuous splash screen for this panel.

Change-Id: I491adaff98a2ba608c6e1771130687194f9e1b53
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>