dt-bindings: mmc: arasan,sdci: Add power-domains and iommus properties

ZynqMP SDHCI Arasan IP core has own power domain and also iommu ID that's
why describe optional power-domains and iommus properties.
Signed-off-by: Michal Simek <michal.simek@amd.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/bf912d5f5e74b43903a84262565f564bfe0fed7e.1691047370.git.michal.simek@amd.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/arasan,sdhci.yaml

@@ -160,6 +160,12 @@ properties:
     description:
       The MIO bank number in which the command and data lines are configured.
 
+  iommus:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
 dependencies:
   '#clock-cells': [ clock-output-names ]