[media] vb2: replace BUG by WARN_ON

No need to oops for this, WARN_ON is good enough.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/v4l2-core/videobuf2-core.c

@@ -2597,9 +2597,9 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
 	/*
 	 * Sanity check
 	 */
-	if ((read && !(q->io_modes & VB2_READ)) ||
-	   (!read && !(q->io_modes & VB2_WRITE)))
-		BUG();
+	if (WARN_ON((read && !(q->io_modes & VB2_READ)) ||
+		    (!read && !(q->io_modes & VB2_WRITE))))
+		return -EINVAL;
 
 	/*
 	 * Check if device supports mapping buffers to kernel virtual space.