arm64: dts: qcom: sdm660-xiaomi-lavender: Configure WLED

WLED is used for controlling display backlight on this phone.

Signed-off-by: Dang Huynh <danct12@riseup.net>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220425032824.211975-1-danct12@riseup.net