wifi: rtw88: Remove duplicate NULL check before calling usb_kill/free_urb()

Both usb_kill_urb() and usb_free_urb() do the NULL check itself, so there
is no need to duplicate it prior to calling.

Fixes: a82dfd33d123 ("wifi: rtw88: Add common USB chip support")
Signed-off-by: Jinjie Ruan <[e-mail]>
Acked-by: Sascha Hauer <[e-mail]>
Acked-by: Ping-Ke Shih <[e-mail]>
Signed-off-by: Kalle Valo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/net/wireless/realtek/rtw88/usb.c

···
 
 	for (i = 0; i < RTW_USB_RXCB_NUM; i++) {
 		rxcb = &rtwusb->rx_cb[i];
-		if (rxcb->rx_urb)
-			usb_kill_urb(rxcb->rx_urb);
+		usb_kill_urb(rxcb->rx_urb);
 	}
 }
 
···
 
 	for (i = 0; i < RTW_USB_RXCB_NUM; i++) {
 		rxcb = &rtwusb->rx_cb[i];
-		if (rxcb->rx_urb) {
-			usb_kill_urb(rxcb->rx_urb);
-			usb_free_urb(rxcb->rx_urb);
-		}
+		usb_kill_urb(rxcb->rx_urb);
+		usb_free_urb(rxcb->rx_urb);
 	}
 }