RDMA/qedr: Add iWARP connection management qp related callbacks

This patch implements the following iWARP callbacks:
qp_add_ref
qp_rem_ref
get_qp

Signed-off-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Signed-off-by: Ram Amrani <Ram.Amrani@cavium.com>
Signed-off-by: Ariel Elior <Ariel.Elior@cavium.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>