iio: light: veml3235: extend regmap to add cache

The configuration and ID registers are not volatile and are not affected
by read operations (i.e. not precious), making them suitable to be
cached in order to reduce the number of accesses to the device.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241224-veml3235_scale-v2-3-2e1286846c77@gmail.com


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