dt-bindings: arm: qcom: Document Lenovo ThinkPad T14s Gen 6 LCD and OLED

dt-bindings: arm: qcom: Document Lenovo ThinkPad T14s Gen 6 LCD and OLED

Due to the difference in how the panel backlight is being handled
between the OLED variant and LCD one, it is required to have two
separate DTBs.

So document the compatible string for both the OLED and LCD variants.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20250314140325.4143779-2-abel.vesa@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>