Merge branch 'net-evaluate-net-ipvX-conf-all-sysctls'

Vincent Bernat says:

====================
net: evaluate net.ipvX.conf.all.* sysctls

Some per-interface sysctls are ignoring the "all" variant. This
patchset fixes some of them when such a sysctl is handled as a
boolean. This includes:

 - net.ipvX.conf.all.disable_policy
 - net.ipvX.conf.all.disable_policy.disable_xfrm
 - net.ipv4.conf.all.proxy_arp_pvlan
 - net.ipvX.conf.all.ignore_routes_with_linkdown

Two sysctls are still ignoring the "all" variant as it wouldn't make
much sense for them:

 - net.ipv4.conf.all.tag
 - net.ipv4.conf.all.medium_id

Ideally, the "all" variant should be removed, but there is no simple
alternative to DEVINET_SYSCTL_* macros that would allow one to not
expose and "all" entry.
====================

Link: https://lore.kernel.org/r/20201107193515.1469030-1-vincent@bernat.ch
Signed-off-by: Jakub Kicinski <kuba@kernel.org>