staging: r8188eu: remove unused function RT_usb_endpoint_num

RT_usb_endpoint_num is unused. Remove this function.
Acked-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210910202151.4007-4-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/os_dep/usb_intf.c

@@ -88,11 +88,6 @@ static inline int RT_usb_endpoint_is_bulk_out(const struct usb_endpoint_descript
 	return RT_usb_endpoint_xfer_bulk(epd) && RT_usb_endpoint_dir_out(epd);
 }
 
-static inline int RT_usb_endpoint_num(const struct usb_endpoint_descriptor *epd)
-{
-	return epd->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
-}
-
 static u8 rtw_init_intf_priv(struct dvobj_priv *dvobj)
 {
 	u8 rst = _SUCCESS;