soc/intel/skylake: Add integrated LAN config parameters

Add parameters to configure the integrated LAN via FSP.  Since
this takes over a PCI CLKREQ# pin it needs to know which pin
it should use, and there are additional parameters for LTR and
a "K1 power save" feature.

This was tested on a KBL-R board with integrated LAN, verifying
that the device is functional under Linux with the e1000e driver.

Change-Id: Idb200cec90a3c0d4d9c914bae9983a3bcdafcd06
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/22856
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/skylake/chip.h

@@ -135,6 +135,10 @@ struct soc_intel_skylake_config {
 
 	/* Lan */
 	u8 EnableLan;
+	u8 EnableLanLtr;
+	u8 EnableLanK1Off;
+	u8 LanClkReqSupported;
+	u8 LanClkReqNumber;
 
 	/* SATA related */
 	u8 EnableSata;