usb: ehci: ehci-marvell: Support for marvell,ac5-ehci

Unlike the other 64-bit mvebu SoCs the AlleyCat5 uses the older ehci
block from the 32-bit SoCs. Adapt the ehci-marvell.c driver to cope with
the fact that the ac5 does not have the mbus infrastructure the 32-bit
SoCs have and ensure USB_EHCI_IS_TDI is selected.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>