xfs: kill some warnings on i386 builds

Randy Dunlap Reported printk() format-related warnings reported
on i386 builds in his environment.  Dave Chinner provided this
patch to eliminate them.

Signed-off by: Dave Chinner <david@fromorbit.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>

Signed-off-by: Alex Elder <aelder@sgi.com>