net/mlx5e: Add missing capability check for uplink follow

Expose firmware indication that it supports setting eswitch uplink state
to follow (follow the physical link). Condition setting the eswitch
uplink admin-state with this capability bit. Older FW may not support
the uplink state setting.

Fixes: 7d0314b11cdd ("net/mlx5e: Modify uplink state on interface up/down")
Signed-off-by: Aya Levin <[e-mail]>
Reviewed-by: Moshe Shemesh <[e-mail]>
Signed-off-by: Saeed Mahameed <[e-mail]>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

···
 
 	mlx5_set_port_admin_status(mdev, state);
 
-	if (mlx5_eswitch_mode(mdev) != MLX5_ESWITCH_LEGACY)
+	if (mlx5_eswitch_mode(mdev) == MLX5_ESWITCH_OFFLOADS ||
+	    !MLX5_CAP_GEN(mdev, uplink_follow))
 		return;
 
 	if (state == MLX5_PORT_UP)

include/linux/mlx5/mlx5_ifc.h

···
 	u8	   ece_support[0x1];
 	u8	   reserved_at_a4[0x7];
 	u8         log_max_srq[0x5];
-	u8         reserved_at_b0[0x2];
+	u8         reserved_at_b0[0x1];
+	u8         uplink_follow[0x1];
 	u8         ts_cqe_to_dest_cqn[0x1];
 	u8         reserved_at_b3[0xd];