dt-bindings: reset: Add syscon to nuvoton ma35d1 system-management node

Add a compatible 'syscon' to the system management node since the system
control registers are mapped by this driver. The other driver must access
the system control registers through 'regmap' using a phandle that
references this node.
Signed-off-by: Jacky Huang <ychuang3@nuvoton.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20240521012447.42211-2-ychuang570808@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/reset/nuvoton,ma35d1-reset.yaml

@@ -18,6 +18,7 @@ properties:
   compatible:
     items:
       - const: nuvoton,ma35d1-reset
+      - const: syscon
 
   reg:
     maxItems: 1
@@ -37,7 +38,7 @@ examples:
   - |
 
     system-management@40460000 {
-        compatible = "nuvoton,ma35d1-reset";
+        compatible = "nuvoton,ma35d1-reset", "syscon";
         reg = <0x40460000 0x200>;
         #reset-cells = <1>;
     };