igmp: Fix data-races around sysctl_igmp_qrv.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949


Upstream Status: linux.git
Conflicts: Drop the drivers/net/amt.c chunk (the AMT driver doesn't
           exist in Centos Stream).

commit 8ebcc62c
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date:   Fri Jul 15 10:17:44 2022 -0700

    igmp: Fix data-races around sysctl_igmp_qrv.

    While reading sysctl_igmp_qrv, it can be changed concurrently.
    Thus, we need to add READ_ONCE() to its readers.

    This test can be packed into a helper, so such changes will be in the
    follow-up series after net is merged into net-next.

      qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

    Fixes: a9fe8e29 ("ipv4: implement igmp_qrv sysctl to tune igmp robustness variable")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Guillaume Nault <gnault@redhat.com>