e1000e: add ethtool .get_eee/.set_eee

Add the ability to query and set Energy Efficient Ethernet parameters via
ethtool for applicable devices.

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>
diff --git a/drivers/net/ethernet/intel/e1000e/hw.h b/drivers/net/ethernet/intel/e1000e/hw.h
index 06239fe..81afad5 100644
--- a/drivers/net/ethernet/intel/e1000e/hw.h
+++ b/drivers/net/ethernet/intel/e1000e/hw.h
@@ -62,6 +62,7 @@
 	E1000_IVAR     = 0x000E4, /* Interrupt Vector Allocation - RW */
 	E1000_EITR_82574_BASE = 0x000E8, /* Interrupt Throttling - RW */
 #define E1000_EITR_82574(_n) (E1000_EITR_82574_BASE + (_n << 2))
+	E1000_LPIC     = 0x000FC, /* Low Power Idle Control - RW */
 	E1000_RCTL     = 0x00100, /* Rx Control - RW */
 	E1000_FCTTV    = 0x00170, /* Flow Control Transmit Timer Value - RW */
 	E1000_TXCW     = 0x00178, /* Tx Configuration Word - RW */