net: bridge: use nla_total_size_64bit() in br_get_linkxstats_size()

net: bridge: use nla_total_size_64bit() in br_get_linkxstats_size()

bridge_fill_linkxstats() is using nla_reserve_64bit().

We must use nla_total_size_64bit() instead of nla_total_size()
for corresponding data structure.

Fixes: 6774caed7674 ("net: bridge: add support for IGMP/MLD stats and export them via netlink")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nikolay Aleksandrov <nikolay@nvidia.com>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>