ipv4: igmp: annotate data-races in igmp_heard_query()

ipv4: igmp: annotate data-races in igmp_heard_query()

Multiple cpus can run igmp_heard_query() concurrently.

Add missing READ_ONCE()/WRITE_ONCE() over following in_dev fields.

- mr_qrv
- mr_qi
- mr_qri
- mr_v1_seen
- mr_v2_seen

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+ae9a171f239b14485310@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/69f38675.050a0220.3cbe47.0002.GAE@google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260430164836.872079-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>