IB/Verbs: Use management helper rdma_cap_ib_smi()

Introduce helper rdma_cap_ib_smi() to help us check if the port of an
IB device support Infiniband Subnet Management Interface.

Signed-off-by: Michael Wang <yun.wang@profitbricks.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --cc drivers/infiniband/core/agent.c
Simple merge

diff --cc drivers/infiniband/core/mad.c
Simple merge

diff --cc include/rdma/ib_verbs.h
Simple merge