nexthop: fix uninitialized variable in nla_put_nh_group_stats()

The "*hw_stats_used" value needs to be set on the success paths to prevent
an uninitialized variable bug in the caller, nla_put_nh_group_stats().

Fixes: 5072ae0 ("net: nexthop: Expose nexthop group HW stats to user space")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/f08ac289-d57f-4a1a-830f-cf9a0563cb9c@moroto.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/nexthop.c

@@ -768,8 +768,10 @@ static int nh_grp_hw_stats_update(struct nexthop *nh, bool *hw_stats_used)
 	struct net *net = nh->net;
 	int err;
 
-	if (nexthop_notifiers_is_empty(net))
+	if (nexthop_notifiers_is_empty(net)) {
+		*hw_stats_used = false;
 		return 0;
+	}
 
 	err = nh_notifier_grp_hw_stats_init(&info, nh);
 	if (err)