ice: do not setup vlan for loopback VSI

Currently loopback test is failiing due to the error returned from
ice_vsi_vlan_setup(). Skip calling it when preparing loopback VSI.

Fixes: 0e674aeb ("ice: Add handler for ethtool selftest")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_main.c

@@ -6013,10 +6013,12 @@ int ice_vsi_cfg(struct ice_vsi *vsi)
 	if (vsi->netdev) {
 		ice_set_rx_mode(vsi->netdev);
 
-		err = ice_vsi_vlan_setup(vsi);
+		if (vsi->type != ICE_VSI_LB) {
+			err = ice_vsi_vlan_setup(vsi);
 
-		if (err)
-			return err;
+			if (err)
+				return err;
+		}
 	}
 	ice_vsi_cfg_dcb_rings(vsi);