IB/hfi1: Enable RDMA_CAP_OPA_AH in hfi driver to support extended LIDs

Enabling this bit helps core components query for extended address
support using the rdma_cap_opa_ah interface.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Don Hiatt <don.hiatt@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>