xfs: allow setting full range of panic tags

xfs will not allow combining other panic masks with
XFS_PTAG_VERIFIER_ERROR.

 # sysctl fs.xfs.panic_mask=511
 sysctl: setting key "fs.xfs.panic_mask": Invalid argument
 fs.xfs.panic_mask = 511

Update to the maximum value that can be set to allow the full range of
masks. Do this using a mask of possible values to prevent this happening
again as suggested by Darrick.

Fixes: d519da41

 ("xfs: Introduce XFS_PTAG_VERIFIER_ERROR panic mask")
Signed-off-by: Donald Douwsma <ddouwsma@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>