iio: tsl2772: Use devm_iio_device_register

Use devm_iio_device_register, which removes the tsl2772_remove
function.

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Reviewed-by: Brian Masney <masneyb@onstation.org>
Tested-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>