iio: proximity: vcnl3020: pass struct vcnl3020_property by pointer

Pass struct vcnl3020_property by pointer instead of by value to avoid
copying the entire struct.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250628-iio-const-data-25-v1-1-5d99cf17790e@baylibre.com


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