block: Set BIO_TRACE_COMPLETION on new bio during split

We inadvertently set it again on the source bio, but we need
to set it on the new split bio instead.

Fixes: fbbaf700 ("block: trace completion of all bios.")
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio.c

@@ -1808,7 +1808,7 @@ struct bio *bio_split(struct bio *bio, int sectors,
 	bio_advance(bio, split->bi_iter.bi_size);
 
 	if (bio_flagged(bio, BIO_TRACE_COMPLETION))
-		bio_set_flag(bio, BIO_TRACE_COMPLETION);
+		bio_set_flag(split, BIO_TRACE_COMPLETION);
 
 	return split;
 }