e1000e: alternate MAC address update

If word 0x37 in the EEPROM is 0xFFFF _or_ 0x0000, then there is no
alternate MAC address in the EEPROM.
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/e1000e/lib.c

@@ -201,10 +201,10 @@ s32 e1000_check_alt_mac_addr_generic(struct e1000_hw *hw)
 		goto out;
 	}
 
-	if (nvm_alt_mac_addr_offset == 0xFFFF) {
+	if ((nvm_alt_mac_addr_offset == 0xFFFF) ||
+	    (nvm_alt_mac_addr_offset == 0x0000))
 		/* There is no Alternate MAC Address */
 		goto out;
-	}
 
 	if (hw->bus.func == E1000_FUNC_1)
 		nvm_alt_mac_addr_offset += E1000_ALT_MAC_ADDRESS_OFFSET_LAN1;