usb: udc: tegra: select USB_ROLE_SWITCH

Without this, this new driver fails to link:

drivers/usb/gadget/udc/tegra-xudc.o: In function `tegra_xudc_remove':
tegra-xudc.c:(.text+0x19d4): undefined reference to `usb_role_switch_unregister'
drivers/usb/gadget/udc/tegra-xudc.o: In function `tegra_xudc_probe':
tegra-xudc.c:(.text+0x2a34): undefined reference to `usb_role_switch_register'
drivers/usb/gadget/udc/tegra-xudc.o: In function `tegra_xudc_usb_role_sw_work':
tegra-xudc.c:(.text+0x4b64): undefined reference to `usb_role_switch_get_role'

Fixes: 49db4272

 ("usb: gadget: Add UDC driver for tegra XUSB device mode controller")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20191216131831.3228566-1-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>