xfs_repair: validate superblock against known v5 feature flags

xfs_repair: validate superblock against known v5 feature flags

Apparently xfs_repair running on a v5 filesystem doesn't check the
compat, rocompat, or incompat feature flags for bits that it doesn't
know about, which means that old xfs_repairs can wreak havoc.  So,
strengthen the checks to prevent repair from "repairing" anything it
doesn't understand.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Fanael Linithien <fanael4@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>