sunxi-mmc: Add support for A20

Make sunxi-mmcm build (and work!) with sun7i as arch.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi-ehci/ohci: Add support for A20

And we've working USB (for the 2 regular controllers) !

Signed-off-by: Hans de Goede <hdegoede@redhat.com>