[XFS] Make quiet mounts quiet

The XFS quiet mount logic was inverted making quiet mounts noisy and vice
versa. Fix it.

SGI-PV: 958469
SGI-Modid: xfs-linux-melb:xfs-kern:27520a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Tim Shimmin <tes@sgi.com>