mv643xx_eth: Fix use of uninitialized port_num field

In this driver, the default ethernet address is first set by by calling
eth_port_uc_addr_get() which reads the relevant registers of the
corresponding port as initially set by firmware. However that function
used the port_num field accessed through the private area of net_dev
before it was set.

The result was that one board I have ended up with the unicast address
set to 00:00:00:00:00:00 (only port 1 is connected on this board). The
problem appeared after commit 84dd619e4dc3b0b1c40dafd98c90fd950bce7bc5.

This patch fixes the bug by setting mp->port_num prior to calling
eth_port_uc_get_addr().

Signed-off-by: Gabriel Paubert <paubert@iram.es>
Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/mv643xx_eth.c

@@ -1379,7 +1379,7 @@ static int mv643xx_eth_probe(struct platform_device *pdev)
 
 	spin_lock_init(&mp->lock);
 
-	port_num = pd->port_number;
+	port_num = mp->port_num = pd->port_number;
 
 	/* set default config values */
 	eth_port_uc_addr_get(dev, dev->dev_addr);
@@ -1411,8 +1411,6 @@ static int mv643xx_eth_probe(struct platform_device *pdev)
 	duplex = pd->duplex;
 	speed = pd->speed;
 
-	mp->port_num = port_num;
-
 	/* Hook up MII support for ethtool */
 	mp->mii.dev = dev;
 	mp->mii.mdio_read = mv643xx_mdio_read;