net/mlx5e: Fix tc_tun.h to verify MLX5_ESWITCH config

Exclude contents of tc_tun.h header when CONFIG_MLX5_ESWITCH is disabled to
prevent compile-time errors when compiling with such config.

Fixes: 0d9f964 ("net/mlx5e: Extract tc tunnel encap/decap code to dedicated file")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.h

@@ -11,6 +11,8 @@
 #include "en.h"
 #include "en_rep.h"
 
+#ifdef CONFIG_MLX5_ESWITCH
+
 enum {
 	MLX5E_TC_TUNNEL_TYPE_UNKNOWN,
 	MLX5E_TC_TUNNEL_TYPE_VXLAN,
@@ -99,4 +101,6 @@ int mlx5e_tc_tun_parse_udp_ports(struct mlx5e_priv *priv,
 				 void *headers_c,
 				 void *headers_v);
 
+#endif /* CONFIG_MLX5_ESWITCH */
+
 #endif //__MLX5_EN_TC_TUNNEL_H__