arm64: dts: qcom: msm8998-fxtec-pro1: Add physical keyboard leds

Add configuration for the physical keyboard LEDs, including the
caps lock indicator and keyboard backlight.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210909123823.368199-2-angelogioacchino.delregno@somainline.org