tg3: Add 5720 PHY ID

This patch adds the 5720 PHY ID.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.h b/drivers/net/tg3.h
index a936727..e7880d5 100644
--- a/drivers/net/tg3.h
+++ b/drivers/net/tg3.h
@@ -3035,6 +3035,7 @@
 #define TG3_PHY_ID_BCM5718S		0xbc050ff0
 #define TG3_PHY_ID_BCM57765		0x5c0d8a40
 #define TG3_PHY_ID_BCM5719C		0x5c0d8a20
+#define TG3_PHY_ID_BCM5720C		0x5c0d8b60
 #define TG3_PHY_ID_BCM5906		0xdc00ac40
 #define TG3_PHY_ID_BCM8002		0x60010140
 #define TG3_PHY_ID_INVALID		0xffffffff