btrfs: use BLK_STS defines where needed

At few places we could use BLK_STS_OK and BLK_STS_NOSUPP.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Satoru Taekeuchi <satoru.takeuchi@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ dropped first hunk btrfs_endio_direct_read ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -255,7 +255,8 @@ static void end_compressed_bio_write(struct bio *bio)
 					 cb->start,
 					 cb->start + cb->len - 1,
 					 NULL,
-					 bio->bi_status ? 0 : 1);
+					 bio->bi_status ?
+					 BLK_STS_OK : BLK_STS_NOTSUPP);
 	cb->compressed_pages[0]->mapping = NULL;
 
 	end_compressed_writeback(inode, cb);

fs/btrfs/inode.c

@@ -8485,7 +8485,7 @@ static void btrfs_end_dio_bio(struct bio *bio)
 	if (dip->errors) {
 		bio_io_error(dip->orig_bio);
 	} else {
-		dip->dio_bio->bi_status = 0;
+		dip->dio_bio->bi_status = BLK_STS_OK;
 		bio_endio(dip->orig_bio);
 	}
 out:

fs/btrfs/volumes.c

@@ -6029,7 +6029,7 @@ static void btrfs_end_bio(struct bio *bio)
 			 * this bio is actually up to date, we didn't
 			 * go over the max number of errors
 			 */
-			bio->bi_status = 0;
+			bio->bi_status = BLK_STS_OK;
 		}
 
 		btrfs_end_bbio(bbio, bio);