net: w5100-spi: add support to specify MAC address by device tree

This adds support to specify the MAC address by 'mac-address' or
'local-mac-address' properties in the device tree.  These are common
properties for the Ethernet controller.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Mike Sinkovsky <msink@permonline.ru>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/wiznet/w5100-spi.c b/drivers/net/ethernet/wiznet/w5100-spi.c
index b868e45..93a2d3c 100644
--- a/drivers/net/ethernet/wiznet/w5100-spi.c
+++ b/drivers/net/ethernet/wiznet/w5100-spi.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/netdevice.h>
+#include <linux/of_net.h>
 #include <linux/spi/spi.h>
 
 #include "w5100.h"
@@ -414,6 +415,7 @@
 	const struct spi_device_id *id = spi_get_device_id(spi);
 	const struct w5100_ops *ops;
 	int priv_size;
+	const void *mac = of_get_mac_address(spi->dev.of_node);
 
 	switch (id->driver_data) {
 	case W5100:
@@ -432,7 +434,7 @@
 		return -EINVAL;
 	}
 
-	return w5100_probe(&spi->dev, ops, priv_size, NULL, spi->irq, -EINVAL);
+	return w5100_probe(&spi->dev, ops, priv_size, mac, spi->irq, -EINVAL);
 }
 
 static int w5100_spi_remove(struct spi_device *spi)