xfs: don't fail repairs on metadata files with no attr fork

Fix a minor bug where we fail repairs on metadata files that do not have
attr forks because xrep_metadata_inode_subtype doesn't filter ENOENT.

Cc: stable@vger.kernel.org # v6.8
Fixes: 5a8e07e7 ("xfs: repair the inode core and forks of a metadata inode")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>