xfs: fix data fork format filtering during inode repair

xfs: fix data fork format filtering during inode repair

Coverity noticed that xrep_dinode_bad_metabt_fork never runs because
XFS_DINODE_FMT_META_BTREE is always filtered out in the mode selection
switch of xrep_dinode_check_dfork.

Metadata btrees are allowed only in the data forks of regular files, so
add this case explicitly.  I guess this got fubard during a refactoring
prior to 6.13 and I didn't notice until now. :/

Coverity-id: 1617714
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>