i40e: Fix adding ADQ filter to TC0

Procedure of configure tc flower filters erroneously allows to create
filters on TC0 where unfiltered packets are also directed by default.
Issue was caused by insufficient checks of hw_tc parameter specifying
the hardware traffic class to pass matching packets to.

Fix checking hw_tc parameter which blocks creation of filters on TC0.

Fixes: 2f4b411 ("i40e: Enable cloud filters via tc-flower")
Signed-off-by: Grzegorz Szczurek <grzegorzx.szczurek@intel.com>
Signed-off-by: Jedrzej Jagielski <jedrzej.jagielski@intel.com>
Tested-by: Bharathi Sreenivas <bharathi.sreenivas@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -8542,6 +8542,11 @@ static int i40e_configure_clsflower(struct i40e_vsi *vsi,
 		return -EOPNOTSUPP;
 	}
 
+	if (!tc) {
+		dev_err(&pf->pdev->dev, "Unable to add filter because of invalid destination");
+		return -EINVAL;
+	}
+
 	if (test_bit(__I40E_RESET_RECOVERY_PENDING, pf->state) ||
 	    test_bit(__I40E_RESET_INTR_RECEIVED, pf->state))
 		return -EBUSY;