staging: iio: tsl2x7x: various comment cleanups

This patch removes several unnecessary comments, changes some comments
so that the use as much of the allowable 80 characters as possible, adds
the proper whitespace, removes some structure members from the kernel
docs that are no longer present, and improves the existing kernel doc
information for some existing structure members.

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