staging: iio: tsl2x7x: simplify device id verification

This patch renames tsl2x7x_device_id() to tsl2x7x_device_id_verif(),
removes the unnecessary pointer on the id parameter, and only calls
the verification function once.

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