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/p54/p54common.c b/drivers/net/wireless/p54/p54common.c
index b3e75eb..b3c297e 100644
--- a/drivers/net/wireless/p54/p54common.c
+++ b/drivers/net/wireless/p54/p54common.c
@@ -1192,10 +1192,11 @@
 	p54_set_filter(dev, 0, NULL);
 }
 
-static int p54_config(struct ieee80211_hw *dev, struct ieee80211_conf *conf)
+static int p54_config(struct ieee80211_hw *dev, u32 changed)
 {
 	int ret;
 	struct p54_common *priv = dev->priv;
+	struct ieee80211_conf *conf = &dev->conf;
 
 	mutex_lock(&priv->conf_mutex);
 	priv->rx_antenna = 2; /* automatic */