Description: net: fix possible store tearing in neigh_periodic_work()
References:
Notes:
 carnil> Introduced in 767e97e1e0db ("neigh: RCU conversion of struct neighbour").
 carnil> Vulnerable versions: 2.6.37-rc1.
Bugs:
upstream: released (6.6-rc5) [25563b581ba3a1f263a00e8c9a97f5e7363be6fd]
6.7-upstream-stable: N/A "Fixed before branching point"
6.6-upstream-stable: N/A "Fixed before branching point"
6.1-upstream-stable: released (6.1.57) [f82aac8162871e87027692b36af335a2375d4580]
5.10-upstream-stable: released (5.10.198) [2ea52a2fb8e87067e26bbab4efb8872639240eb0]
4.19-upstream-stable: needed
sid: released (6.5.8-1)
6.1-bookworm-security: released (6.1.64-1)
5.10-bullseye-security: released (5.10.205-1)
4.19-buster-security: needed