qcacld-3.0: Report valid MCS index to upper layer

While processing get_station cfg operation, HDD is using Nss
value, which gets updated during association, to calculate data
rate. So, there is a possibility of driver to report invalid
MCS index to upper layer if association happens with Nss 2 and
when data transmission is happening at Nss 1 rate.

On receiving GET STATS response, calculate Nss value based upon
the current data rate received from firmware, and pass it to HDD,
so that HDD can use the same Nss value to report valid MCS index
to the upper layer.

Change-Id: I62f029d53149a4747f619027ce69ce65fb280b8d
CRs-Fixed: 2250993

core/wma/inc/wma_api.h

@@ -392,5 +392,5 @@ void wma_wmi_stop(void);
  *  Return: mcs index
  */
 uint8_t wma_get_mcs_idx(uint16_t max_rate, uint8_t rate_flags,
-			uint8_t nss, uint8_t *mcs_rate_flag);
+			uint8_t *nss, uint8_t *mcs_rate_flag);
 #endif