IB/qib: Remove set-but-not-used variables

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Tested-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Acked-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>