e1000e: PHY type cleanups in e1000e_check_downshift()

Remove the case for 82577 because it does not support the ability to check
for downshift.  Add case for e1000_phy_bm which can do this.
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/e1000e/phy.c

@@ -1525,8 +1525,8 @@ s32 e1000e_check_downshift(struct e1000_hw *hw)
 	switch (phy->type) {
 	case e1000_phy_m88:
 	case e1000_phy_gg82563:
+	case e1000_phy_bm:
 	case e1000_phy_82578:
-	case e1000_phy_82577:
 		offset	= M88E1000_PHY_SPEC_STATUS;
 		mask	= M88E1000_PSSR_DOWNSHIFT;
 		break;