block: blk-merge: remove unnecessary check

In this case, 'sectors' can't be zero at all, so remove the check
and let the bio be split.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-merge.c

@@ -129,9 +129,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
 				nsegs++;
 				sectors = max_sectors;
 			}
-			if (sectors)
-				goto split;
-			/* Make this single bvec as the 1st segment */
+			goto split;
 		}
 
 		if (bvprvp && blk_queue_cluster(q)) {