staging: iio: tsl2x7x: rename driver to tsl2772

This patch renames this driver from tsl2x7x to tsl2772 since it is
highly likely that additional devices will be added to this driver that
do not match that wildcard. The tsl2772 driver name was selected since
that is currently the device with the most features that are supported
by this driver.

This patch also adds Brian Masney's copyright to tsl2772.h for all of
the work that has been done to move this driver out of staging.

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