dt-bindings: iio: light: ltrf216a: Document LTR-308 support

Document LiteOn LTR-308 support in LTR-F216A bindings.

The two devices seem to have almost identical register map, except that
the LTR-308 does not have three CLEAR_DATA registers, which are unused
by this driver. Furthermore, LTR-308 and LTR-F216A use different lux
calculation constants, 0.6 and 0.45 respectively.

https://optoelectronics.liteon.com/upload/download/DS86-2016-0027/LTR-308ALS_Final_%20DS_V1%201.pdf
https://optoelectronics.liteon.com/upload/download/DS86-2019-0016/LTR-F216A_Final_DS_V1.4.PDF

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20240708114227.18283-1-marex@denx.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>