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.c b/drivers/net/tg3.c
index 263f151..886174d 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -14673,6 +14673,7 @@
 	case TG3_PHY_ID_BCM5718S:	return "5718S";
 	case TG3_PHY_ID_BCM57765:	return "57765";
 	case TG3_PHY_ID_BCM5719C:	return "5719C";
+	case TG3_PHY_ID_BCM5720C:	return "5720C";
 	case TG3_PHY_ID_BCM8002:	return "8002/serdes";
 	case 0:			return "serdes";
 	default:		return "unknown";