iio: accel: bmi088: Drop manual assignment of iio_dev.dev.parent

The core already set this to the same value in devm_iio_device_alloc()

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Mike Looijmans <mike.looijmans@topic.nl>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426170251.351957-2-jic23@kernel.org