nb/intel: Deduplicate vbt header

Move header and delete duplicates.

Change-Id: I0e1f5d9082626062f95afe718f6ec62a68f0d828
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/18903
Tested-by: build bot (Jenkins)
Tested-by: coreboot org <coreboot.org@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/northbridge/intel/sandybridge/gma.c

@@ -27,6 +27,7 @@
 
 #include "chip.h"
 #include "sandybridge.h"
+#include "gma.h"
 
 struct gt_powermeter {
 	u16 reg;