e1000e: 82577/8 must acquire h/w semaphore before workaround

The workaround function e1000_configure_k1_pchlan() assumes the h/w
semaphore is already acquired.  This was originally missed when setting up
the part for the ethtool loopback test.
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/e1000e/ethtool.c

@@ -1249,6 +1249,7 @@ static int e1000_integrated_phy_loopback(struct e1000_adapter *adapter)
 	u32 ctrl_reg = 0;
 	u32 stat_reg = 0;
 	u16 phy_reg = 0;
+	s32 ret_val = 0;
 
 	hw->mac.autoneg = 0;
 
@@ -1308,7 +1309,13 @@ static int e1000_integrated_phy_loopback(struct e1000_adapter *adapter)
 	case e1000_phy_82577:
 	case e1000_phy_82578:
 		/* Workaround: K1 must be disabled for stable 1Gbps operation */
+		ret_val = hw->phy.ops.acquire(hw);
+		if (ret_val) {
+			e_err("Cannot setup 1Gbps loopback.\n");
+			return ret_val;
+		}
 		e1000_configure_k1_ich8lan(hw, false);
+		hw->phy.ops.release(hw);
 		break;
 	case e1000_phy_82579:
 		/* Disable PHY energy detect power down */