iio: position: hid-sensor-custom-intel-hinge: Drop duplicate parent setting.

iio_dev.dev.parent is already set to the same value in
devm_iio_device_alloc()

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ye Xiang <xiang.ye@intel.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426170251.351957-8-jic23@kernel.org