dt-bindings: nand: meson: Fix 'nand-rb' property

Add description of 'nand-rb' property. Use "Fixes" because this property
must be supported since the beginning.

Fixes: fbc00b5e ("dt-bindings: nand: meson: convert txt to yaml")
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230608044728.1328506-2-AVKrasnov@sberdevices.ru

Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml

@@ -58,6 +58,11 @@ patternProperties:
             meson-gxl-nfc 8, 16, 24, 30, 40, 50, 60
             meson-axg-nfc 8
 
+      nand-rb:
+        maxItems: 1
+        items:
+          maximum: 0
+
 required:
   - compatible
   - reg
@@ -87,6 +92,7 @@ examples:
 
       nand@0 {
         reg = <0>;
+        nand-rb = <0>;
       };
     };