Add support to enable/disable builtin GbE (again)

This requires a new system agent binary (v6 / v11 on haswell).
Note that the existing system agent binaries are long time obsolete
and won't work with current coreboot, so this update is overdue.

Change-Id: I48d8649576ca84d2b85ab082ce06f3462e189059
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/3568
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/src/northbridge/intel/sandybridge/pei_data.h b/src/northbridge/intel/sandybridge/pei_data.h
index fb56873..d317515 100644
--- a/src/northbridge/intel/sandybridge/pei_data.h
+++ b/src/northbridge/intel/sandybridge/pei_data.h
@@ -38,7 +38,7 @@
 } pch_usb3_controller_settings;
 
 typedef void (*tx_byte_func)(unsigned char byte);
-#define PEI_VERSION 5
+#define PEI_VERSION 6
 
 struct pei_data
 {
@@ -61,6 +61,7 @@
 	uint8_t ts_addresses[4];
 	int boot_mode;
 	int ec_present;
+	int gbe_enable;
 	// 0 = leave channel enabled
 	// 1 = disable dimm 0 on channel
 	// 2 = disable dimm 1 on channel