ARM: dts: sun8i: Use sun8i-reference-design-tablet for gt90h dts

This results in quite a nice cleanup for this dts file.

As an added bonus this also enables full otg support. I've tested that
this works as advertised.

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