IB/hfi1: Fix a kernel-doc warning

Avoid that building with W=1 causes the following warning to appear:

drivers/infiniband/hw/hfi1/qp.c:484: warning: Cannot understand * on line 484 - I thought it was a doc line

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>