xfs: use deferred intent items for reaping crosslinked blocks

When we're removing rmap records for crosslinked blocks, use deferred
intent items so that we can try to free/unmap as many of the old data
structure's blocks as we can in the same transaction as the commit.

Cc: <stable@vger.kernel.org> # v6.6
Fixes: 1c7ce115 ("xfs: reap large AG metadata extents when possible")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>