devlink: health: Fix nla_nest_end in error flow

devlink_nl_health_reporter_fill() error flow calls nla_nest_end(). Fix
it to call nla_nest_cancel() instead.

Note the bug is harmless as genlmsg_cancel() cancel the entire message,
so no fixes tag added.
Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/devlink/leftover.c

@@ -6028,7 +6028,7 @@ devlink_nl_health_reporter_fill(struct sk_buff *msg,
 	return 0;
 
 reporter_nest_cancel:
-	nla_nest_end(msg, reporter_attr);
+	nla_nest_cancel(msg, reporter_attr);
 genlmsg_cancel:
 	genlmsg_cancel(msg, hdr);
 	return -EMSGSIZE;