ACPI / HED: constify ACPI device ids

Constify the acpi_hed_ids[] ACPI device IDs array -- no need to have it
writeable.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/hed.c

@@ -27,7 +27,7 @@
 #include <linux/acpi.h>
 #include <acpi/hed.h>
 
-static struct acpi_device_id acpi_hed_ids[] = {
+static const struct acpi_device_id acpi_hed_ids[] = {
 	{"PNP0C33", 0},
 	{"", 0},
 };