IB/qib: Remove mmap from qib

Since mmap functionality has been moved into rdmavt, its time for qib to
use that.

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>