staging: the DWC2 driver uses bus_to_virt

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dwc2/Kconfig

 config USB_DWC2
 	tristate "DesignWare USB2 DRD Core Support"
 	depends on USB
+	depends on VIRT_TO_BUS
 	select USB_OTG_UTILS
 	help
 	  Say Y or M here if your system has a Dual Role HighSpeed