ice: block SF port creation in legacy mode

There is no support for SF in legacy mode. Reflect it in the code.

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Fixes: eda69d6 ("ice: add basic devlink subfunctions support")
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Michal Swiatkowski

drivers/net/ethernet/intel/ice/devlink/devlink_port.c

@@ -989,5 +989,11 @@ ice_devlink_port_new(struct devlink *devlink,
 	if (err)
 		return err;
 
+	if (!ice_is_eswitch_mode_switchdev(pf)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "SF ports are only supported in eswitch switchdev mode");
+		return -EOPNOTSUPP;
+	}
+
 	return ice_alloc_dynamic_port(pf, new_attr, extack, devlink_port);
 }