xfs: widen ondisk quota expiration timestamps to handle y2038+

xfs: widen ondisk quota expiration timestamps to handle y2038+

Source kernel commit: 4ea1ff3b49681af45a4a8c14baf7f0b3d11aa74a

Enable the bigtime feature for quota timers.  We decrease the accuracy
of the timers to ~4s in exchange for being able to set timers up to the
bigtime maximum.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>