drivers/intel/gma/opregion: migrate from nb/common

Migrate opregion code from northbridge/intel/common to
drivers/intel/gma in preparation for consolidation with
soc/intel/common opregion code. Rename init_igd_opregion()
for clarity and disambiguation with other implementations.

Change-Id: I2d0bae98f04dbe7e896ca34e15f24d29b6aa2ed6
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/20582
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
diff --git a/src/northbridge/intel/sandybridge/gma.c b/src/northbridge/intel/sandybridge/gma.c
index db24dda..2751b3a 100644
--- a/src/northbridge/intel/sandybridge/gma.c
+++ b/src/northbridge/intel/sandybridge/gma.c
@@ -25,7 +25,7 @@
 #include <cpu/x86/msr.h>
 #include <cpu/x86/mtrr.h>
 #include <southbridge/intel/bd82x6x/nvs.h>
-#include <northbridge/intel/common/gma_opregion.h>
+#include <drivers/intel/gma/opregion.h>
 #include <cbmem.h>
 
 #include "chip.h"
@@ -698,7 +698,7 @@
 	igd_opregion_t *opregion = (igd_opregion_t *)current;
 	global_nvs_t *gnvs;
 
-	if (init_igd_opregion(opregion) != CB_SUCCESS)
+	if (intel_gma_init_igd_opregion(opregion) != CB_SUCCESS)
 		return current;
 
 	current += sizeof(igd_opregion_t);