Looking for feedback on this quickie patch.  This enables netlink to 
deliver link-change events, as reported by drivers via 
netif_carrier_{on,off}.

* We could use a different RTM than NEWLINK (RTM_LINKCHANGE?) if we care
* We could do notifier_call_chain(netdev_chain) with NETDEV_UP or 
NETDEV_LINKCHANGE (new) if we care

comments?
-- 
Tim Hockin
Systems Software Engineer
Sun Microsystems, Linux Kernel Engineering
thockin@sun.com