dt-bindings: display: mediatek: dpi: add power-domains example

DPI is part of the display / multimedia block in MediaTek SoCs, and
always have a power-domain (at least in the upstream device-trees).
Add the power-domains property to the binding example.

Fixes: 9273cf7d3942 ("dt-bindings: display: mediatek: convert the dpi bindings to yaml")
Signed-off-by: Fabien Parent <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Reviewed-by: CK Hu <[e-mail]>
Signed-off-by: Alexandre Mergnat <[e-mail]>
Link: https://patchwork.kernel.org/project/dri-devel/patch/[e-mail]/
Signed-off-by: Chun-Kuang Hu <[e-mail]>

Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.yaml

···
   - |
     #include <dt-bindings/interrupt-controller/arm-gic.h>
     #include <dt-bindings/clock/mt8173-clk.h>
+    #include <dt-bindings/power/mt8173-power.h>
 
     dpi: dpi@1401d000 {
         compatible = "mediatek,mt8173-dpi";
         reg = <0x1401d000 0x1000>;
         interrupts = <GIC_SPI 194 IRQ_TYPE_LEVEL_LOW>;
+        power-domains = <&spm MT8173_POWER_DOMAIN_MM>;
         clocks = <&mmsys CLK_MM_DPI_PIXEL>,
              <&mmsys CLK_MM_DPI_ENGINE>,
              <&apmixedsys CLK_APMIXED_TVDPLL>;