f2fs: fix wrong return value of f2fs_bmap_compress()

If compression is disable, we should return zero rather than -EOPNOTSUPP
to indicate f2fs_bmap() is not supported.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -3703,10 +3703,9 @@ static sector_t f2fs_bmap_compress(struct inode *inode, sector_t block)
 	}
 
 	f2fs_put_dnode(&dn);
-
 	return blknr;
 #else
-	return -EOPNOTSUPP;
+	return 0;
 #endif
 }