iwlwifi: align set channel with mac80211

This patch makes use of mac80211 defaults for channel and band.
Older code that uses G band channel 6 was removed. This patch also
changes iwl_set_rxon_channel signature.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 7b8af96..df5763c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2841,7 +2841,7 @@
 	)
 		priv->staging_rxon.flags = 0;
 
-	iwl_set_rxon_channel(priv, conf->channel->band, channel);
+	iwl_set_rxon_channel(priv, conf->channel);
 
 	iwl_set_flags_for_band(priv, conf->channel->band);