mlxsw: switchx2: Add IB port support

SwitchX-2 is IB capable device. This patch add a support to change the
port type between Ethernet and Infiniband.

When the port is set to IB, the FW implements the Subnet Management Agent
(SMA) manage the port. All port attributes can be control remotely by
the SM.

Usage:
	$ devlink port show
	pci/0000:03:00.0/1: type eth netdev eth0
	pci/0000:03:00.0/3: type eth netdev eth1
	pci/0000:03:00.0/5: type eth netdev eth2
	pci/0000:03:00.0/6: type eth netdev eth3
	pci/0000:03:00.0/8: type eth netdev eth4

	$ devlink port set pci/0000:03:00.0/1 type ib

	$ devlink port show
	pci/0000:03:00.0/1: type ib

Signed-off-by: Elad Raz <eladr@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>