staging: iio: tsl2x7x: use device defaults for als_time, prox_time and wait_time

This patch changes the defaults of the als_time, prox_time and
wait_time to match the defaults according to the TSL2772 datasheet.

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