Define 'struct mlx5_dev_attr' which is ibv and dv independent. It
contains attribute that were originally contained in 'struct
ibv_device_attr_ex' and 'struct mlx5dv_context dv_attr'. Add a new API
mlx5_os_get_dev_attr() which fills in the new defined struct.
Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>