dt-bindings: mtd: renesas: Fix the NAND controller description

Add the missing power-domain property which is needed on all the
RZ/N1 SoC IPs.

Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20220513104957.257721-2-miquel.raynal@bootlin.com

Documentation/devicetree/bindings/mtd/renesas-nandc.yaml

@@ -36,11 +36,15 @@ properties:
       - const: hclk
       - const: eclk
 
+  power-domains:
+    maxItems: 1
+
 required:
   - compatible
   - reg
   - clocks
   - clock-names
+  - power-domains
   - interrupts
 
 unevaluatedProperties: false
@@ -56,6 +60,7 @@ examples:
         interrupts = <GIC_SPI 58 IRQ_TYPE_LEVEL_HIGH>;
         clocks = <&sysctrl R9A06G032_HCLK_NAND>, <&sysctrl R9A06G032_CLK_NAND>;
         clock-names = "hclk", "eclk";
+        power-domains = <&sysctrl>;
         #address-cells = <1>;
         #size-cells = <0>;
     };