net/mlx5: Improve functions documentation

Fix documentation of mlx5_eq_enable/disable to cleanup compiler warnings.

drivers/net/ethernet/mellanox/mlx5/core//eq.c:334:
warning: Function parameter or member 'dev' not described in 'mlx5_eq_enable'
warning: Function parameter or member 'eq' not described in 'mlx5_eq_enable'
warning: Function parameter or member 'nb' not described in 'mlx5_eq_enable'

drivers/net/ethernet/mellanox/mlx5/core//eq.c:355:
warning: Function parameter or member 'dev' not described in 'mlx5_eq_disable'
warning: Function parameter or member 'eq' not described in 'mlx5_eq_disable'
warning: Function parameter or member 'nb' not described in 'mlx5_eq_disable'

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>