bd82x6x, ibexpeak, lynxpoint: Ensure 0-filling of uninited GNVS vars.

Change-Id: I672c3ca9e7f30a21330cf1920a25b1ab38b3f282
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7015
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

src/southbridge/intel/bd82x6x/lpc.c

@@ -33,6 +33,7 @@
 #include <arch/acpigen.h>
 #include <drivers/intel/gma/i915.h>
 #include <cbmem.h>
+#include <string.h>
 #include "pch.h"
 #include "nvs.h"
 
@@ -680,6 +681,9 @@ static unsigned long southbridge_fill_ssdt(unsigned long current, const char *oe
 
 	if (gnvs) {
 		int scopelen;
+
+		memset(gnvs, 0, sizeof (*gnvs));
+
 		acpi_create_gnvs(gnvs);
 		/* IGD OpRegion Base Address */
 		gnvs->aslb = (u32)opregion;