[media] videobuf2-core: remove duplicated code

Remove duplicated test of buffer presence at streamon

Signed-off-by: Victor Lambret <[e-mail]>
Acked-by: Marek Szyprowski <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

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

···
 		return -EINVAL;
 	}
 
-	if (!q->num_buffers) {
-		dprintk(1, "no buffers have been allocated\n");
-		return -EINVAL;
-	}
 	if (q->num_buffers < q->min_buffers_needed) {
 		dprintk(1, "need at least %u allocated buffers\n",
 				q->min_buffers_needed);