mac80211: introduce hw config change flags

This makes mac80211 notify the driver which configuration
actually changed, e.g. channel etc.

No driver changes, this is just plumbing, driver authors are
expected to act on this if they want to.

Also remove the HW CONFIG debug printk, it's incorrect, often
we configure something else.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rtl8180_dev.c b/drivers/net/wireless/rtl8180_dev.c
index 9de8f57..e8d2239 100644
--- a/drivers/net/wireless/rtl8180_dev.c
+++ b/drivers/net/wireless/rtl8180_dev.c
@@ -692,9 +692,10 @@
 	priv->vif = NULL;
 }
 
-static int rtl8180_config(struct ieee80211_hw *dev, struct ieee80211_conf *conf)
+static int rtl8180_config(struct ieee80211_hw *dev, u32 changed)
 {
 	struct rtl8180_priv *priv = dev->priv;
+	struct ieee80211_conf *conf = &dev->conf;
 
 	priv->rf->set_chan(dev, conf);