phy: sun4i: Add H616 USB PHY support

Now that the Allwinner USB PHY driver supports the H616 quirk, let's
enable support for USB ports on that SoC.

We connect the compatible string to a new struct describing the SoCs USB
PHY properties, and unblock the PHY driver selection in Kconfig.

A later patch will enable USB support in the H616 boards' defconfigs.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>