tg3 / broadcom: Optionally disable TXC if no link

This patch adds code to disable the TXC and RXC reference clocks if link
is not available.

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 f74bf91..50bb53d 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -1103,6 +1103,7 @@
 	case TG3_PHY_ID_BCM50610M:
 		phydev->dev_flags |= PHY_BRCM_CLEAR_RGMII_MODE |
 				     PHY_BRCM_RX_REFCLK_UNUSED |
+				     PHY_BRCM_DIS_TXCRXC_NOENRGY |
 				     PHY_BRCM_AUTO_PWRDWN_ENABLE;
 		if (tp->tg3_flags3 & TG3_FLG3_RGMII_STD_IBND_DISABLE)
 			phydev->dev_flags |= PHY_BRCM_STD_IBND_DISABLE;