netlink: add netlink handler for gring (-g)

Implement "ethtool -g <dev>" subcommand using ETHTOOL_MSG_RINGS_GET netlink
message. This retrieves and displays device ring sizes, traditionally
provided by ETHTOOL_GRINGPARAM ioctl request.

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

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