net/mlx5_core: Get vendor-id using the query adapter command

Add two wrapper functions to the query adapter command:

1. mlx5_query_board_id -- replaces the old mlx5_cmd_query_adapter.

2. mlx5_core_query_vendor_id -- retrieves the vendor_id from the
   query_adapter command.

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>