mlxsw: spectrum_router: Fix rif counter freeing routine

During rif counter freeing the counter index can be invalid. Add check
of validity before freeing the counter.

Fixes: e0c0afd8 ("mlxsw: spectrum: Support for counters on router interfaces")
Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -206,6 +206,9 @@ void mlxsw_sp_rif_counter_free(struct mlxsw_sp *mlxsw_sp,
 {
 	unsigned int *p_counter_index;
 
+	if (!mlxsw_sp_rif_counter_valid_get(rif, dir))
+		return;
+
 	p_counter_index = mlxsw_sp_rif_p_counter_get(rif, dir);
 	if (WARN_ON(!p_counter_index))
 		return;