rsi: fix for low throughput issue

observed low throughput rates during verification. This is because, QoS
enable flag is overridden by sequence number in the data descriptor frame.
Hence, added the fix for same.
Signed-off-by: Siva Rebbagondla <siva.rebbagondla@redpinesignals.com>
Signed-off-by: Sushant Kumar Mishra <sushant.mishra@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rsi/rsi_91x_hal.c

@@ -246,7 +246,7 @@ int rsi_prepare_data_desc(struct rsi_common *common, struct sk_buff *skb)
 		}
 	}
 
-	data_desc->mac_flags = cpu_to_le16(seq_num & 0xfff);
+	data_desc->mac_flags |= cpu_to_le16(seq_num & 0xfff);
 	data_desc->qid_tid = ((skb->priority & 0xf) |
 			      ((tx_params->tid & 0xf) << 4));
 	data_desc->sta_id = tx_params->sta_id;