dt-bindings: sram: sunxi-sram: Add regulators child

Some sunxi SoCs have in-package regulators controlled by a register in
the system control MMIO block. Allow a child node for this regulator
device in addition to SRAM child nodes.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240622150731.1105901-2-wens@kernel.orgSigned-off-by: Chen-Yu Tsai <wens@csie.org>

Documentation/devicetree/bindings/sram/allwinner,sun4i-a10-system-control.yaml

@@ -56,6 +56,9 @@ properties:
   ranges: true
 
 patternProperties:
+  "^regulators@[0-9a-f]+$":
+    $ref: /schemas/regulator/allwinner,sun20i-d1-system-ldos.yaml#
+
   "^sram@[a-f0-9]+":
     $ref: /schemas/sram/sram.yaml#
     unevaluatedProperties: false
@@ -130,3 +133,28 @@ examples:
         };
       };
     };
+
+  - |
+    syscon@3000000 {
+      compatible = "allwinner,sun20i-d1-system-control";
+      reg = <0x3000000 0x1000>;
+      ranges;
+      #address-cells = <1>;
+      #size-cells = <1>;
+
+      regulators@3000150 {
+        compatible = "allwinner,sun20i-d1-system-ldos";
+        reg = <0x3000150 0x4>;
+
+        reg_ldoa: ldoa {
+          regulator-min-microvolt = <1800000>;
+          regulator-max-microvolt = <1800000>;
+        };
+
+        reg_ldob: ldob {
+          regulator-name = "vcc-dram";
+          regulator-min-microvolt = <1500000>;
+          regulator-max-microvolt = <1500000>;
+        };
+      };
+    };