mac80211: revamp beacon configuration

This patch changes mac80211's beacon configuration handling
to never pass skbs to the driver directly but rather always
require the driver to use ieee80211_beacon_get(). Additionally,
it introduces "change flags" on the config_interface() call
to enable drivers to figure out what is changing. Finally, it
removes the beacon_update() driver callback in favour of
having IBSS beacon delivered by ieee80211_beacon_get() as well.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c
index 0dd1cb5..8ce1726 100644
--- a/drivers/net/wireless/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/rt2x00/rt2500usb.c
@@ -1775,7 +1775,6 @@
 	.bss_info_changed	= rt2x00mac_bss_info_changed,
 	.conf_tx		= rt2x00mac_conf_tx,
 	.get_tx_stats		= rt2x00mac_get_tx_stats,
-	.beacon_update		= rt2500usb_beacon_update,
 };
 
 static const struct rt2x00lib_ops rt2500usb_rt2x00_ops = {
@@ -1793,6 +1792,7 @@
 	.get_tx_data_len	= rt2500usb_get_tx_data_len,
 	.kick_tx_queue		= rt2500usb_kick_tx_queue,
 	.fill_rxdone		= rt2500usb_fill_rxdone,
+	.beacon_update		= rt2500usb_beacon_update,
 	.config_filter		= rt2500usb_config_filter,
 	.config_intf		= rt2500usb_config_intf,
 	.config_erp		= rt2500usb_config_erp,