iio: vcnl4000: add VCNL4010 and VCNL4020 device id

The driver already supports VCNL4010/20 devices. The currently supported
features and detectable product id are the same, so add shared id for
them.

This is a groundwork to extend the driver by detecting incorrectly
specified device id.

Signed-off-by: Tomas Novotny <tomas@novotny.cz>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>