ARM: dts: sun5i: a10s: Fix HDMI output DTC warning

Our HDMI output endpoint on the A10s DTSI has a warning under DTC: "graph
node has single child node 'endpoint', #address-cells/#size-cells are not
necessary". Fix this by removing those properties.

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