dts: bindings: pinctrl: sifli,sf32lb52-pinmux: add port/offset cells

So we can reference later to any of the PAD_XX_YY registers from e.g.
GPIO nodes, where we need to write pad configs like pull-ups.

Signed-off-by: Gerard Marull-Paretas <[email protected]>

Author: gmarull

dts/arm/sifli/sf32lb52x.dtsi

@@ -88,6 +88,7 @@
 			reg = <0x50003000 0x34>, <0x50003034 0xb4>;
 			reg-names = "pad_sa", "pad_pa";
 			clocks = <&rcc_clk SF32LB52X_CLOCK_PINMUX1>;
+			#sifli,pinmux-cells = <2>;
 			sifli,cfg = <&cfg>;
 			status = "disabled";
 		};

dts/bindings/pinctrl/sifli,sf32lb52x-pinmux.yaml

@@ -91,6 +91,14 @@ properties:
   sifli,cfg:
     required: true
 
+  "#sifli,pinmux-cells":
+    type: int
+    const: 2
+
+sifli,pinmux-cells:
+  - port
+  - offset
+
 child-binding:
   child-binding:
     include: