iio: fix devm_iio_trigger_alloc with parent.cocci

iio: fix devm_iio_trigger_alloc with parent.cocci

Use cocci semantic patch:
@@
expression trigger, P;
@@
   trigger = devm_iio_trigger_alloc(P, ...);
   ...
-  trigger->dev.parent = P;

To remove trigger->dev.parent, since it is set by default.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210309193620.2176163-3-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>