staging: iio: light: Add breaks to lengthy lines

This fixes three instances of checkpatch warning:
WARNING: line over 80 characters

Signed-off-by: George Edward Bulmer <gebulmer@googlemail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>