net/mlx4: Add mlx4_SET_VPORT_QOS implementation

Add the SET_VPORT_QOS device command, which is ntended for virtual
granular QoS configuration per VF in SRIOV mode. The SET_VPORT_QOS
command sets and queries QoS parameters of a VPort. Each priority
allowed for a VPort is assigned with a share of the BW, and a BW
limitation. QoS parameters can be modified at any time, but must be
initialized before any QP is associated with the VPort.

Signed-off-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>