mv643xx_eth: fix unicast address filter corruption on mtu change

When mv643xx_eth_open() is called to up an interface, port_start()
will first re-program the unicast address filter, and then
re-initialise the PORT_CONFIG register, but that will disable unicast
promiscuous mode if it was enabled by the unicast address filter setup.

This isn't a problem on ifconfig up, as ->set_rx_mode() will be called
shortly afterwards which will program the filters again, but it does
trigger when changing the MTU, which calls mv643xx_eth_stop() and then
mv643xx_eth_open() by hand to repopulate the receive rings with skbuffs
of the new size.

Swap the initialisation of the PORT_START register and the call to
the unicast filter setup function to fix this.
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/mv643xx_eth.c

@@ -2029,11 +2029,6 @@ static void port_start(struct mv643xx_eth_private *mp)
 		txq_set_fixed_prio_mode(txq);
 	}
 
-	/*
-	 * Add configured unicast address to address filter table.
-	 */
-	mv643xx_eth_program_unicast_filter(mp->dev);
-
 	/*
 	 * Receive all unmatched unicast, TCP, UDP, BPDU and broadcast
 	 * frames to RX queue #0, and include the pseudo-header when
@@ -2046,6 +2041,11 @@ static void port_start(struct mv643xx_eth_private *mp)
 	 */
 	wrlp(mp, PORT_CONFIG_EXT, 0x00000000);
 
+	/*
+	 * Add configured unicast addresses to address filter table.
+	 */
+	mv643xx_eth_program_unicast_filter(mp->dev);
+
 	/*
 	 * Enable the receive queues.
 	 */