Merge branch 'net-bridge-drop-hosts-limit-sysfs-and-add-a-comment'

Nikolay Aleksandrov says:

====================
net: bridge: drop hosts limit sysfs and add a comment

As recently discussed[1] we should stop extending the bridge sysfs
support for new options and move to using netlink only, so patch 01
drops the recently added hosts limit sysfs support which is still in
net-next only and patch 02 adds comments in br_sysfs_br/if.c to warn
against adding new sysfs options.

[1] https://lore.kernel.org/netdev/20210128105201.7c6bed82@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/T/#mda7265b2e57b52bdab863f286efa85291cf83822
====================

Link: https://lore.kernel.org/r/20210129115142.188455-2-razor@blackwall.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>