V4L/DVB: cx231xx: improve error handling

Return -EINVAL if we don't find the control id.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/cx231xx/cx231xx-video.c

···
 	if (c->id < V4L2_CID_BASE || c->id >= V4L2_CID_LASTP1)
 		return -EINVAL;
 	if (c->id == V4L2_CID_AUDIO_MUTE) {
-		for (i = 0; i < CX231XX_CTLS; i++)
+		for (i = 0; i < CX231XX_CTLS; i++) {
 			if (cx231xx_ctls[i].v.id == c->id)
 				break;
+		}
+		if (i == CX231XX_CTLS)
+			return -EINVAL;
 		*c = cx231xx_ctls[i].v;
 	} else
 		*c = no_ctl;