IB/hfi1: Replace kmalloc and memcpy with a kmemdup

This change was recommended by Coccinelle tool when I ran the command:
-bash-4.2$ make coccicheck MODE=patch M=drivers/infiniband/hw/hfi1/

Reviewed-by: Jubin John <jubin.john@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>