net/mlx5: Add support for setting VF min rate

Add support for SRIOV VF min rate guarantee by using the TSAR BW share
weights mechanism.

The TSAR BW share vport attribute represents the weight of that vport
among the other vports weights which means that the actual vport BW
percentage is the same vport weight percentage among the total vports
weights sum.

Signed-off-by: Mohamad Haj Yahia <mohamad@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>