USB: Fix USB Kconfig dependency problem on 85xx/QoirQ platforms
For FSL PPC SoCs USB_ARCH_HAS_EHCI currently on depends on PPC_83xx.
However that excludes support for USB on 85xx & QorIQ devices. Use
FSL_SOC insted which will get us 83xx, 85xx, QorIQ, and 5xxx which all
have the same USB IP on them.