r8169: simplify rtl8169_alloc_rx_data

dev->dev.parent has the same value as tp_to_dev(tp)
(set by SET_NETDEV_DEV() in rtl_init_one()) and we know it can't be NULL.
This allows us to simplify the code.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -6731,8 +6731,7 @@ static struct sk_buff *rtl8169_alloc_rx_data(struct rtl8169_private *tp,
 	void *data;
 	dma_addr_t mapping;
 	struct device *d = tp_to_dev(tp);
-	struct net_device *dev = tp->dev;
-	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
+	int node = dev_to_node(d);
 
 	data = kmalloc_node(rx_buf_sz, GFP_KERNEL, node);
 	if (!data)