Today, RDMA capabilities are learned from management firmware
which provides a per-device indication for all interfaces.
Newer management firmware is capable of providing a per-device
indication [would later be extended to either RoCE/iWARP].

Try using this newer learning mechanism, but fallback in case
management firmware is too old to retain current functionality.
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>