ASoC: dt-bindings: loongson,ls2k1000-i2s: Document Loongson-2K0300 compatible

Add a new compatible string `loongson,ls2k0300-i2s` for the I2S
controller found on Loongson-2K0300 SoC.

Unlike Loongson-2K1000, Loongson-2K0300 does not require the second
register region for APB DMA configuration, so update the binding to
allow a single reg entry.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Link: https://patch.msgid.link/af092f9eabdc170c3d7951b29eee6512f748eb48.1782439646.git.zhoubinbin@loongson.cn
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/loongson,ls2k1000-i2s.yaml

@@ -14,9 +14,12 @@ allOf:
 
 properties:
   compatible:
-    const: loongson,ls2k1000-i2s
+    enum:
+      - loongson,ls2k0300-i2s
+      - loongson,ls2k1000-i2s
 
   reg:
+    minItems: 1
     items:
       - description: Loongson I2S controller Registers.
       - description: APB DMA config register for Loongson I2S controller.
@@ -49,6 +52,23 @@ required:
 
 unevaluatedProperties: false
 
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - loongson,ls2k1000-i2s
+
+then:
+  properties:
+    reg:
+      minItems: 2
+
+else:
+  properties:
+    reg:
+      maxItems: 1
+
 examples:
   - |
     #include <dt-bindings/clock/loongson,ls2k-clk.h>