device: Constify struct device * parameter to write_acpi_tables

.write_acpi_tables() should not be updating the device structure. This
change makes the struct device * argument to it as const.

Change-Id: I50d013e83a404e0a0e3837ca16fa75c7eaa0e14a
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40701
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
diff --git a/src/northbridge/intel/sandybridge/gma.c b/src/northbridge/intel/sandybridge/gma.c
index 5c4f548..ad94e06 100644
--- a/src/northbridge/intel/sandybridge/gma.c
+++ b/src/northbridge/intel/sandybridge/gma.c
@@ -647,7 +647,8 @@
 	drivers_intel_gma_displays_ssdt_generate(&chip->gfx);
 }
 
-static unsigned long gma_write_acpi_tables(struct device *const dev, unsigned long current,
+static unsigned long gma_write_acpi_tables(const struct device *const dev,
+					   unsigned long current,
 					   struct acpi_rsdp *const rsdp)
 {
 	igd_opregion_t *opregion = (igd_opregion_t *)current;