iwlwifi: move tx fail code to agn

The code to print out TX failure reasons is
AGN specific, so it can be in the AGN module.

Signed-off-by: Johannes Berg <johannes.berg@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 632ea4b..d6645ec 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -248,8 +248,10 @@
 void iwlagn_bt_cancel_deferred_work(struct iwl_priv *priv);
 
 #ifdef CONFIG_IWLWIFI_DEBUG
+const char *iwl_get_tx_fail_reason(u32 status);
 const char *iwl_get_agg_tx_fail_reason(u16 status);
 #else
+static inline const char *iwl_get_tx_fail_reason(u32 status) { return ""; }
 static inline const char *iwl_get_agg_tx_fail_reason(u16 status) { return ""; }
 #endif