ARM: sun5i: a10s-olinuxino: Enable HDMI

The A10s Olinuxino has an HDMI connector. Make sure we can use it.

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