btrfs: defrag: use btrfs_mod_outstanding_extents in cluster_pages_for_defrag

btrfs: defrag: use btrfs_mod_outstanding_extents in cluster_pages_for_defrag

[ Upstream commit 28c4a3e21ad030d7571ee9b1b246a5cbfd886627 ]

Since commit 8b62f87bad9c ("Btrfs: rework outstanding_extents"),
manual operations of outstanding_extent in btrfs_inode are replaced by
btrfs_mod_outstanding_extents().
The one in cluster_pages_for_defrag seems to be lost, so replace it
of btrfs_mod_outstanding_extents().

Fixes: 8b62f87bad9c ("Btrfs: rework outstanding_extents")
Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>