rtlwifi: Fix warnings in usb.c

Building this driver with "make W=1" results in the following 2 warnings:

drivers/net/wireless/rtlwifi/usb.c:829:21: warning: variable ‘urb_list’ set but not used [-Wunused-but-set-variable]
drivers/net/wireless/rtlwifi/usb.c:828:23: warning: variable ‘skb_list’ set but not used [-Wunused-but-set-variable]
Signed-off-by: NLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtlwifi/usb.c

@@ -825,8 +825,6 @@ static void _rtl_usb_transmit(struct ieee80211_hw *hw, struct sk_buff *skb,
 	u32 ep_num;
 	struct urb *_urb = NULL;
 	struct sk_buff *_skb = NULL;
-	struct sk_buff_head *skb_list;
-	struct usb_anchor *urb_list;
 
 	WARN_ON(NULL == rtlusb->usb_tx_aggregate_hdl);
 	if (unlikely(IS_USB_STOP(rtlusb))) {
@@ -836,7 +834,6 @@ static void _rtl_usb_transmit(struct ieee80211_hw *hw, struct sk_buff *skb,
 		return;
 	}
 	ep_num = rtlusb->ep_map.ep_mapping[qnum];
-	skb_list = &rtlusb->tx_skb_queue[ep_num];
 	_skb = skb;
 	_urb = _rtl_usb_tx_urb_setup(hw, _skb, ep_num);
 	if (unlikely(!_urb)) {
@@ -844,7 +841,6 @@ static void _rtl_usb_transmit(struct ieee80211_hw *hw, struct sk_buff *skb,
 			 "Can't allocate urb. Drop skb!\n");
 		return;
 	}
-	urb_list = &rtlusb->tx_pending[ep_num];
 	_rtl_submit_tx_urb(hw, _urb);
 }