staging: iio: tsl2x7x: use macro to populate tsl2X7X_device_info

This patch creates a macro that populates the tsl2X7X_device_info
structure to reduce duplicated code in the driver.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>