This adds a netlink channel put helper, nl80211_msg_put_channel(),
which we will also make use of later for the beacon hints events.
Acked-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>