[media] dvb_usb_v2: make local function dvb_usb_v2_generic_io() static

dvb_usb_v2_generic_io() was not declared. It should be static.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/dvb-usb-v2/dvb_usb_urb.c

@@ -21,7 +21,7 @@
 
 #include "dvb_usb_common.h"
 
-int dvb_usb_v2_generic_io(struct dvb_usb_device *d,
+static int dvb_usb_v2_generic_io(struct dvb_usb_device *d,
 		u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
 {
 	int ret, actual_length;