net/mlx5e: Move TC-specific function definitions into MLX5_CLS_ACT

en_tc.h header file declares several TC-specific functions in
CONFIG_MLX5_ESWITCH block even though those functions are only compiled
when CONFIG_MLX5_CLS_ACT is set, which is a recent change. Move them to
proper block.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Maor Dickman <maord@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>