phy: sun4i-usb: enable PHY0 dual route switching for A64 USB PHY

Allwinner A64 SoC features a switchable PHY0 like the one in H3, which
can switch between a MUSB controller and a pair of OHCI/EHCI controller.

Enable PHY0 route auto switching for A64.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>