[media] em28xx: pass correct buffer size to snprintf

snprintf()'s size parameter includes space for the terminating '\0' character.

Signed-off-by: Chris Rankin <rankincj@yahoo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
index 3e3959f..d947026 100644
--- a/drivers/media/video/em28xx/em28xx-cards.c
+++ b/drivers/media/video/em28xx/em28xx-cards.c
@@ -3154,7 +3154,7 @@
 		goto err;
 	}
 
-	snprintf(dev->name, 29, "em28xx #%d", nr);
+	snprintf(dev->name, sizeof(dev->name), "em28xx #%d", nr);
 	dev->devno = nr;
 	dev->model = id->driver_info;
 	dev->alt   = -1;