ieee802154: add nl802154 framework

This patch adds a basic nl802154 framework. Most of this code was
grabbed from nl80211 framework.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --cc net/ieee802154/Makefile
Simple merge

diff --cc net/ieee802154/core.c
Simple merge

diff --cc net/ieee802154/core.h
Simple merge

diff --cc net/ieee802154/ieee802154.h
Simple merge

diff --cc net/ieee802154/netlink.c
Simple merge

diff --cc net/ieee802154/nl802154.c
Simple merge

diff --cc net/ieee802154/nl802154.h
Simple merge