iwlagn: add testmode set fixed rate command

Add support in testmode for setting fixed rate

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 12fb2f4..ab29ab5 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1521,6 +1521,8 @@
 #ifdef CONFIG_IWLWIFI_DEVICE_SVTOOL
 	struct iwl_testmode_trace testmode_trace;
 #endif
+	u32 dbg_fixed_rate;
+
 }; /*iwl_priv */
 
 static inline void iwl_txq_ctx_activate(struct iwl_priv *priv, int txq_id)