ARM: dts: sun8i: Add support for H3 usb clocks

Add a node describing the usb-clks found on the H3.

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