iio: light: ltr501: Add of_device_id table

Add of_device_id table so the driver can be used on DT platforms without
relying on i2c_device_id fallback. (So DT schema validation is possible)

Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Link: https://lore.kernel.org/r/20211006163058.145842-4-nikita@trvn.ru


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>