usb: dwc3: improve the config dependency of USB_DWC3_XILINX

usb: dwc3: improve the config dependency of USB_DWC3_XILINX

A request to Manish Narani (see Link) asked for clarification of the
reference to the config ARCH_VERSAL in the support of Xilinx SoCs with
DesignWare Core USB3 IP.

As there is no response, clean up the reference to the non-existing config
symbol. While at it, follow up on Felipe Balbi's request to add the
alternative COMPILE_TEST dependency.

Link: https://lore.kernel.org/all/CAKXUXMwgWfX8+OvY0aCwRNukencwJERAZzU7p4eOLXQ2zv6rAg@mail.gmail.com/
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20221116110444.8340-1-lukas.bulwahn@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>