netlink: add netlink handler for gchannels (-l)

Implement "ethtool -l <dev>" subcommand using ETHTOOL_MSG_CHANNELS_GET
netlink message. This retrieves and displays device channel counts,
traditionally provided by ETHTOOL_GCHANNELS ioctl request.

Also register the callback with monitor code so that the monitor can
display ETHTOOL_MSG_CHANNELS_NTF notifications.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
6 files changed