iio: adc: meson_saradc: Don't attach managed resource to IIO device object

iio: adc: meson_saradc: Don't attach managed resource to IIO device object

It feels wrong and actually inconsistent to attach managed resources
to the IIO device object, which is child of the physical device object.
The rest of the ->probe() calls do that against physical device.

Resolve this by reassigning managed resources to the physical device object.

Suggested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20220603100004.70336-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>