ARM: sun7i: dt: Add USB host nodes to a20-olinuxino-micro dts

Add nodes for the usb-phy and ehci- and ohci-usb-host controllers.

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