Squashed commit of the following:
Fix up some final compile isses.
net/netdev: Convert the network down notification logic to use the new wqueue-based notification factility.
net/udp: Convert the UDP readahead notification logic to use the new wqueue-based notification factility.
net/tcp: Convert the TCP readahead notification logic to use the new wqueue-based notification factility.
mm/iob: Convert the IOB notification logic to use the new wqueue-based notification factility.
sched/wqueue: Signals are not good IPCs to support the target poll functionality for several reasons including the amount of data that can be passed with a signal and in the fact that in protected and kernel modes, user threads executing signal handlers in protected, kernel memory is problematic. Instead, convert the same logic to perform the notifications via function callback on the high priority work queue.
net/netdev: Add implementation of if_nametoindex() and if indextoname().
net/pkt: Raw AF_PACKET sockets now depend on CONFIG_NETDEV_IFINDEX.
net/procfs: Tweak to handle traversal of interfaces if CONFIG_NETDEV_IFINDEX is not defined.
net/netdev.h: Update netdev_findbyaddr() to use the assigned device index.
Trivial typo fix
net/netdev: Add support for assigned an interface index to a device when it is regisgtered.
