device: Constify struct device * parameter to acpi_fill_ssdt()

.acpi_fill_ssdt() does not need to modify the device structure. This
change makes the struct device * parameter to acpi_fill_ssdt() as
const.

Change-Id: I110f4c67c3b6671c9ac0a82e02609902a8ee5d5c
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40710
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/intel/common/block/graphics/graphics.c b/src/soc/intel/common/block/graphics/graphics.c
index a6d45c6..5392958 100644
--- a/src/soc/intel/common/block/graphics/graphics.c
+++ b/src/soc/intel/common/block/graphics/graphics.c
@@ -39,7 +39,7 @@
 	return NULL;
 }
 
-static void gma_generate_ssdt(struct device *device)
+static void gma_generate_ssdt(const struct device *device)
 {
 	const struct i915_gpu_controller_info *gfx = intel_igd_get_controller_info(device);