ARM: dts: sun8i: a23/a33: Fix Display Engine DTC warnings

Our display engine endpoints trigger some DTC warnings due to the fact that
we're having a single endpoint that doesn't need any reg property, and
since we don't have a reg property, we don't need the address-cells and
size-cells properties anymore.

Fix those

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