dt-bindings: soc: loongson,ls2k-pmc: Use fallbacks for ls2k-pmc compatible

The Loongson-2K series chips (ls2k0500/ls2k1000/ls2k2000) share the same
PM system controller, using ls2k0500 compatible as fallback for the
others.
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/soc/loongson/loongson,ls2k-pmc.yaml

@@ -11,11 +11,16 @@ maintainers:
 
 properties:
   compatible:
-    items:
-      - enum:
-          - loongson,ls2k0500-pmc
-          - loongson,ls2k1000-pmc
-      - const: syscon
+    oneOf:
+      - items:
+          - const: loongson,ls2k0500-pmc
+          - const: syscon
+      - items:
+          - enum:
+              - loongson,ls2k1000-pmc
+              - loongson,ls2k2000-pmc
+          - const: loongson,ls2k0500-pmc
+          - const: syscon
 
   reg:
     maxItems: 1
@@ -44,7 +49,7 @@ examples:
     #include <dt-bindings/interrupt-controller/irq.h>
 
     power-management@1fe27000 {
-        compatible = "loongson,ls2k1000-pmc", "syscon";
+        compatible = "loongson,ls2k1000-pmc", "loongson,ls2k0500-pmc", "syscon";
         reg = <0x1fe27000 0x58>;
         interrupt-parent = <&liointc1>;
         interrupts = <11 IRQ_TYPE_LEVEL_LOW>;