mv643xx_eth: Check ETH_INT_CAUSE_STATE bit

Commit 468d09f8 masked the "state"
interrupt (bit 20 of the cause register). This results in Radstone's
PPC7D repeatedly re-entering the interrupt routine, locking up the
board. The following patch returns the required handling for this
interrupt.
Signed-off-by: Martyn Welch <martyn.welch@radstone.co.uk>
Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/mv643xx_eth.c

@@ -534,7 +534,7 @@ static irqreturn_t mv643xx_eth_int_handler(int irq, void *dev_id)
 	}
 
 	/* PHY status changed */
-	if (eth_int_cause_ext & ETH_INT_CAUSE_PHY) {
+	if (eth_int_cause_ext & (ETH_INT_CAUSE_PHY | ETH_INT_CAUSE_STATE)) {
 		struct ethtool_cmd cmd;
 
 		if (mii_link_ok(&mp->mii)) {

drivers/net/mv643xx_eth.h

@@ -64,7 +64,9 @@
 #define ETH_INT_CAUSE_TX_ERROR	(ETH_TX_QUEUES_ENABLED << 8)
 #define ETH_INT_CAUSE_TX	(ETH_INT_CAUSE_TX_DONE | ETH_INT_CAUSE_TX_ERROR)
 #define ETH_INT_CAUSE_PHY	0x00010000
-#define ETH_INT_UNMASK_ALL_EXT	(ETH_INT_CAUSE_TX | ETH_INT_CAUSE_PHY)
+#define ETH_INT_CAUSE_STATE	0x00100000
+#define ETH_INT_UNMASK_ALL_EXT	(ETH_INT_CAUSE_TX | ETH_INT_CAUSE_PHY | \
+					ETH_INT_CAUSE_STATE)
 
 #define ETH_INT_MASK_ALL	0x00000000
 #define ETH_INT_MASK_ALL_EXT	0x00000000