ARM: dts: omap4-droid4: add panel orientation

Add information about panel orientation, so that the
system boots into a properly rotated shell.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>