IB/hfi1: Split copy_to_user data copy for better security

A copy_to_user() call assumes that two members of a data structure
are sequential.  Since this may not always be true, separate the copies
to ensure a safe copy.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>