net/mlx5_core: Add new query HCA vport commands

Added the implementation for the following commands:

1. QUERY_HCA_VPORT_GID
2. QUERY_HCA_VPORT_PKEY
3. QUERY_HCA_VPORT_CONTEXT

They will be needed when we move to work with ISSI > 0 in the IB driver too.

Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>