rtlwifi: Use dev_kfree_skb_irq instead of kfree_skb

It is not allowed to call kfree_skb() from hardware interrupt
context or with interrupts being disabled, spin_lock_irqsave()
make sure always in irq disable context. So the kfree_skb()
should be replaced with dev_kfree_skb_irq().

This is detected by Coccinelle semantic patch.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/core.c

@@ -1832,7 +1832,7 @@ bool rtl_cmd_send_packet(struct ieee80211_hw *hw, struct sk_buff *skb)
 
 	spin_lock_irqsave(&rtlpriv->locks.irq_th_lock, flags);
 	pskb = __skb_dequeue(&ring->queue);
-	kfree_skb(pskb);
+	dev_kfree_skb_irq(pskb);
 
 	/*this is wrong, fill_tx_cmddesc needs update*/
 	pdesc = &ring->desc[0];