Drop 'size' argument from bio_endio and bi_end_io

As bi_end_io is only called once when the reqeust is complete,
the 'size' argument is now redundant.  Remove it.

Now there is no need for bio_endio to subtract the size completed
from bi_size.  So don't do that either.

While we are at it, change bi_end_io to return void.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/md/dm-snap.c

@@ -636,7 +636,7 @@ static void error_bios(struct bio *bio)
 	while (bio) {
 		n = bio->bi_next;
 		bio->bi_next = NULL;
-		bio_io_error(bio, bio->bi_size);
+		bio_io_error(bio);
 		bio = n;
 	}
 }