iio: light: vcnl4000 add support for the VCNL4040 proximity and light sensor

The VCNL4040 is almost identical to the VCNL4200 as far as register
layout goes but just need to check a different ID register location.

Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>