Include iface index in the netlink event

The TrafficController inside netd also get notified when the interface
on device added or removed, and it need both ifaceName and ifaceIndex
information from Netlink event. Add the ifaceIndex in the event can
avoid the TrafficController to run if_nametoindex again when receive
the event.

Bug: 30950746
Bug: 73137611
Test: new interface show up in bpf interface map.
Change-Id: Ia3b4aeb8eff345ce7cf03ccec88f0893cfe125c0