ARM: multi_v7_defconfig: Enable USB phys for UniPhier SoCs

Enable the USB3 and USB2 phys implemented in UniPhier SoCs.
These phys are necessary for dwc3 and ehci controllers driving
the USB ports on Pro4 and PXs2 SoCs.

Since the USB host drivers are already built-in, so only the phy
driver are missing to allow booting with USB devices.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>