ARM: dts: sun4i: Add device nodes for display pipelines

The A10 has two interconnected display pipelines, much like the A31,
but without the DRCs between the backend and TCONs.

Add all the device nodes for them, including the downstream HDMI
controller that we already support.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>