mac80211: dont use interface indices in drivers

This patch gets rid of the if_id stuff where possible in favour of
a new per-virtual-interface structure "struct ieee80211_vif". This
structure is located at the end of the per-interface structure and
contains a variable length driver-use data area.

This has two advantages:
 * removes the need to look up interfaces by if_id, this is better
   for working with network namespaces and performance
 * allows drivers to store and retrieve per-interface data without
   having to allocate own lists/hash tables

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/zd1211rw/zd_mac.c b/drivers/net/wireless/zd1211rw/zd_mac.c
index 7b86930..3409cf9 100644
--- a/drivers/net/wireless/zd1211rw/zd_mac.c
+++ b/drivers/net/wireless/zd1211rw/zd_mac.c
@@ -733,7 +733,8 @@
 	return zd_chip_set_channel(&mac->chip, conf->channel);
 }
 
-static int zd_op_config_interface(struct ieee80211_hw *hw, int if_id,
+static int zd_op_config_interface(struct ieee80211_hw *hw,
+				  struct ieee80211_vif *vif,
 				   struct ieee80211_if_conf *conf)
 {
 	struct zd_mac *mac = zd_hw_mac(hw);