staging: iio: tsl2583: check if chip is in a working state in in_illuminance_calibrat...

staging: iio: tsl2583: check if chip is in a working state in in_illuminance_calibrate_store

in_illuminance_calibrate_store() did not check to see if the chip is
in a working state. This patch adds the proper check. The return value
from taos_als_calibrate() was also not checked in this function, so the
proper check was also added while changes are being made here.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>