phy-sun4i-usb: Add support for the usb-phys on the sun8i-a23 SoC

The usb-phys on the sun8i-a23 SoC have the same setup wrt clocks as on the
sun6i-a31 SoC, but there are only 2 instead of 3 like on the sun5i-a13 SoC.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>