ARM: dts: sun8i-a?3-q8-tablet.dts: Add full otg support

Now that we've all the necessary bits in place we can enable
full otg support on these tablets.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>