iio: light: vcnl4000: add support for Capella CM36686 and CM36672P

iio: light: vcnl4000: add support for Capella CM36686 and CM36672P

Add support for Capella's CM36686 and CM36672P sensors. Capella
CM36686 is an ambient light and proximity sensor that is fully
compatible with VCNL4040 and can be used as is.
CM36672P is partially compatible with VCNL4040 - it uses the same
register fields for proximity sensing, but the ambient light registers
are reserved. For CM36672P, we reuse vcnl4040_channels, but remove the
IIO_LIGHT channel and ambient light integration time.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Erikas Bitovtas <xerikasxx@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>