ARM: dts: qcom: Add LPG node to pm8941

The PM8941 contains 8 LPG channels, as well as TRILED and LUT blocks.
Add a node for these.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20220713212309.130230-2-bjorn.andersson@linaro.org