ARM: dts: sunxi: Add simplefb nodes for "de_be0-lcd0" display pipeline

Add simplefb nodes for "de_be0-lcd0" display pipeline for when u-boot has
set up a pipeline to drive a LCD rather then the HDMI output. The difference
with the existing simplefb node is that this one keeps the HDMI encoder clock
gated.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>