ARM: dts: sun5i: q8-common: Enable display pipeline and LCD display

Q8 form factor A13 tablets have a 7" LCD panel. Unfortunately we
don't know the exact model of the panel. Just pick a panel with
display timings close to what we know.

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