V4L/DVB: em28xx: fix a compilation warning

drivers/media/video/em28xx/em28xx-video.c: In function ‘vidioc_s_register’:
drivers/media/video/em28xx/em28xx-video.c:1617: warning: unused variable ‘rc’
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-video.c

@@ -1614,7 +1614,6 @@ static int vidioc_s_register(struct file *file, void *priv,
 	struct em28xx_fh      *fh  = priv;
 	struct em28xx         *dev = fh->dev;
 	__le16 buf;
-	int    rc;
 
 	switch (reg->match.type) {
 	case V4L2_CHIP_MATCH_AC97: