Bug #5807 - nf_conntrack: nf_conntrack: table full, dropping packet

Disable ipv6 forwarding on the dummy archer interface.

Broadcom suggest that we disable IPv6 on the dummy interface
called 'archer'. This seems to solve the issue with leaking
memory / connection tracking entries.

iopsys-brcm63xx-arm/disc/base-files/etc/sysctl.d/archer.conf

+net.ipv6.conf.archer.disable_ipv6=1

iopsys-brcm63xx-arm/eagle/base-files/etc/sysctl.d/archer.conf

+net.ipv6.conf.archer.disable_ipv6=1

iopsys-brcm63xx-arm/zebra/base-files/etc/sysctl.d/archer.conf

+net.ipv6.conf.archer.disable_ipv6=1