nb/intel/haswell: Simplify GMA SSDT generator

Simplify generation of GMA SSDT, using updated naming convention.
If acpi_fill_ssdt is being invoked, then we know the IGD device is
present and enabled, so we can skip those checks. And the SSDT
generator now checks that the gfx struct is populated, so we can
skip that too.

Change-Id: Icd9caf622dd4c46b13589ebb772138b25888752f
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39948
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/northbridge/intel/haswell/gma.c b/src/northbridge/intel/haswell/gma.c
index c0eaf6d..4c11bd1 100644
--- a/src/northbridge/intel/haswell/gma.c
+++ b/src/northbridge/intel/haswell/gma.c
@@ -524,24 +524,11 @@
 	intel_gma_restore_opregion();
 }
 
-const struct i915_gpu_controller_info *intel_gma_get_controller_info(void)
+static void gma_generate_ssdt(struct device *dev)
 {
-	struct device *dev = pcidev_on_root(2, 0);
-	if (!dev) {
-		return NULL;
-	}
-	struct northbridge_intel_haswell_config *chip = dev->chip_info;
-	return &chip->gfx;
-}
+	const struct northbridge_intel_haswell_config *chip = dev->chip_info;
 
-static void gma_ssdt(struct device *device)
-{
-	const struct i915_gpu_controller_info *gfx = intel_gma_get_controller_info();
-	if (!gfx) {
-		return;
-	}
-
-	drivers_intel_gma_displays_ssdt_generate(gfx);
+	drivers_intel_gma_displays_ssdt_generate(&chip->gfx);
 }
 
 static unsigned long gma_write_acpi_tables(struct device *const dev, unsigned long current,
@@ -573,15 +560,15 @@
 };
 
 static struct device_operations gma_func0_ops = {
-	.read_resources         = pci_dev_read_resources,
-	.set_resources          = pci_dev_set_resources,
-	.enable_resources       = pci_dev_enable_resources,
-	.init                   = gma_func0_init,
-	.acpi_fill_ssdt		= gma_ssdt,
-	.scan_bus               = NULL,
-	.enable                 = NULL,
-	.ops_pci                = &gma_pci_ops,
-	.write_acpi_tables      = gma_write_acpi_tables,
+	.read_resources		= pci_dev_read_resources,
+	.set_resources		= pci_dev_set_resources,
+	.enable_resources	= pci_dev_enable_resources,
+	.init			= gma_func0_init,
+	.acpi_fill_ssdt		= gma_generate_ssdt,
+	.scan_bus		= NULL,
+	.enable			= NULL,
+	.ops_pci		= &gma_pci_ops,
+	.write_acpi_tables	= gma_write_acpi_tables,
 };
 
 static const unsigned short pci_device_ids[] = {