iwlwifi: create iwl_mac80211 unregister routine

The mac80211 setup_register operations are collected in one routine,
but the cleanup routines are not.  Create a routine for this.

Signed-off-by: Don Fry <donald.h.fry@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.h b/drivers/net/wireless/iwlwifi/iwl-agn.h
index 66bcd3e..2c5b6c4 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -91,6 +91,7 @@
 struct ieee80211_hw *iwl_alloc_all(void);
 int iwlagn_mac_setup_register(struct iwl_priv *priv,
 			      struct iwlagn_ucode_capabilities *capa);
+void iwlagn_mac_unregister(struct iwl_priv *priv);
 
 /* RXON */
 int iwlagn_set_pan_params(struct iwl_priv *priv);