mlxsw: spectrum_mr: Fix list iteration in error path

list_for_each_entry_from_reverse() iterates backwards over the list from
the current position, but in the error path we should start from the
previous position.

Fix this by using list_for_each_entry_continue_reverse() instead.

This suppresses the following error from coccinelle:

drivers/net/ethernet/mellanox/mlxsw//spectrum_mr.c:655:34-38: ERROR:
invalid reference to the index variable of the iterator on line 636

Fixes: c011ec1b ("mlxsw: spectrum: Add the multicast routing offloading logic")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -637,11 +637,11 @@ static int mlxsw_sp_mr_vif_resolve(struct mlxsw_sp_mr_table *mr_table,
 	return 0;
 
 err_erif_unresolve:
-	list_for_each_entry_from_reverse(erve, &mr_vif->route_evif_list,
+	list_for_each_entry_continue_reverse(erve, &mr_vif->route_evif_list,
 					     vif_node)
 		mlxsw_sp_mr_route_evif_unresolve(mr_table, erve);
 err_irif_unresolve:
-	list_for_each_entry_from_reverse(irve, &mr_vif->route_ivif_list,
+	list_for_each_entry_continue_reverse(irve, &mr_vif->route_ivif_list,
 					     vif_node)
 		mlxsw_sp_mr_route_ivif_unresolve(mr_table, irve);
 	mr_vif->rif = NULL;