iproute2: add kmod-netlink-diag for ss
Allows proper usage of the ss tool. Otherwise, several errors and bad
data gets thrown:
Cannot open netlink socket: Protocol not supported
Cannot open netlink socket: Protocol not supported
Cannot open netlink socket: Protocol not supported
Cannot open netlink socket: Protocol not supported
Cannot open netlink socket: Protocol not supported
Cannot open netlink socket: Protocol not supported
Cannot open netlink socket: Protocol not supported
Originally reported here: https://github.com/openwrt/packages/issues/8232
Signed-off-by: Rosen Penev <rosenp@gmail.com>