iio: light: veml6030: add support for triggered buffer

iio: light: veml6030: add support for triggered buffer

All devices supported by this driver (currently veml6030, veml6035
and veml7700) have two 16-bit channels, and can profit for the same
configuration to support data access via triggered buffers.

The measurements are stored in two 16-bit consecutive registers
(addresses 0x04 and 0x05) as little endian, unsigned data.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241124-veml6030_triggered_buffer-v3-1-565bb6b4b5c8@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>