xfs: include WARN, REPAIR build options in XFS_BUILD_OPTIONS

The XFS_BUILD_OPTIONS string, shown at module init time and
in modinfo output, does not currently include all available
build options.  So, add in CONFIG_XFS_WARN and CONFIG_XFS_REPAIR.

It has been suggested in some quarters
That this is not enough.
Well ...

Anybody who would like to see this in a sysfs file can send
a patch.  :)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>