iio: light: max44000: use device-managed functions in probe

This is a simple conversion. Both iio_device_register() and
iio_triggered_buffer_setup() functions have device-managed variants.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210913120002.306280-1-aardelean@deviqon.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>