usb: add HAS_IOMEM dependency to USB_NET2272

drivers/usb/gadget/udc/net2272.c: In function ‘net2272_remove’:
drivers/usb/gadget/udc/net2272.c:2232:2: error: implicit declaration of function ‘iounmap’ [-Werror=implicit-function-declaration]
  iounmap(dev->base_addr);
  ^
drivers/usb/gadget/udc/net2272.c: In function ‘net2272_plat_probe’:
drivers/usb/gadget/udc/net2272.c:2650:2: error: implicit declaration of function ‘ioremap_nocache’ [-Werror=implicit-function-declaration]
  dev->base_addr = ioremap_nocache(base, len);
  ^
drivers/usb/gadget/udc/net2272.c:2650:17: warning: assignment makes pointer from integer without a cast [enabled by default]
  dev->base_addr = ioremap_nocache(base, len);
                 ^

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>