iio: kx022a: Use new iio_validate_own_trigger()

The new generic iio_validate_own_trigger() can be used as
validate_trigger callback for verifying the used trigger belongs to same
device as the iio_dev.

Use the generic function instead of rolling own one.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/cbd585e4787f62dc1a343a51b629ce73dd7d5426.1683541225.git.mazziesaccount@gmail.com


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