ASoC: rt5665: constify acpi_device_id.

acpi_device_id are not supposed to change at runtime. All functions
working with acpi_device_id provided by <acpi/acpi_bus.h> work with
const acpi_device_id. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>