soc/intel: Fix ACPI device operations initialization

Initialize ACPI device operations only when CONFIG_HAVE_ACPI_TABLES is
enabled.

BUG=None
TEST=Build Test

Change-Id: I5c5266885d8b08338d17a87bb95110765882120e
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38309
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
diff --git a/src/soc/intel/common/block/graphics/graphics.c b/src/soc/intel/common/block/graphics/graphics.c
index 90931eb..9873059 100644
--- a/src/soc/intel/common/block/graphics/graphics.c
+++ b/src/soc/intel/common/block/graphics/graphics.c
@@ -117,7 +117,9 @@
 	.enable_resources	= pci_dev_enable_resources,
 	.init			= graphics_soc_init,
 	.ops_pci		= &pci_dev_ops_pci,
+#if CONFIG(HAVE_ACPI_TABLES)
 	.write_acpi_tables	= graphics_soc_write_acpi_opregion,
+#endif
 	.scan_bus		= scan_generic_bus,
 };