iwlwifi: Display decoded rate/mcs information

This patch adding MCS information in rate_scale_table, it help for
debugging rate scaling algorithm, easy to understand what is the current
rate scale table and matching modulation, plus the last mcs used for tx.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.h b/drivers/net/wireless/iwlwifi/iwl-agn-rs.h
index 9cd90ba..f875136 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.h
@@ -325,6 +325,13 @@
 #define ANT_BC		(ANT_B | ANT_C)
 #define ANT_ABC		(ANT_AB | ANT_C)
 
+#define IWL_MAX_MCS_DISPLAY_SIZE	12
+
+struct iwl_rate_mcs_info {
+	char	mbps[IWL_MAX_MCS_DISPLAY_SIZE];
+	char	mcs[IWL_MAX_MCS_DISPLAY_SIZE];
+};
+
 static inline u8 num_of_ant(u8 mask)
 {
 	return  !!((mask) & ANT_A) +