dt-bindings: interrupt-controller: loongson,liointc: Fix dtbs_check warning for reg-names

As we know, the Loongson-2K0500 is a single-core CPU, and the core1-
related register (isr1) does not exist. So "reg" and "reg-names" should
be set to "minItems 2"(main nad isr0).

This fixes dtbs_check warning:

DTC_CHK arch/loongarch/boot/dts/loongson-2k0500-ref.dtb
arch/loongarch/boot/dts/loongson-2k0500-ref.dtb: interrupt-controller@1fe11400: reg-names: ['main', 'isr0'] is too short
        From schema: Documentation/devicetree/bindings/interrupt-controller/loongson,liointc.yaml
arch/loongarch/boot/dts/loongson-2k0500-ref.dtb: interrupt-controller@1fe11400: Unevaluated properties are not allowed ('reg-names' was unexpected)
        From schema: Documentation/devicetree/bindings/interrupt-controller/loongson,liointc.yaml
arch/loongarch/boot/dts/loongson-2k0500-ref.dtb: interrupt-controller@1fe11400: reg: [[0, 534844416, 0, 64], [0, 534843456, 0, 8]] is too short
        From schema: Documentation/devicetree/bindings/interrupt-controller/loongson,liointc.yaml
arch/loongarch/boot/dts/loongson-2k0500-ref.dtb: interrupt-controller@1fe11440: reg-names: ['main', 'isr0'] is too short
        From schema: Documentation/devicetree/bindings/interrupt-controller/loongson,liointc.yaml

Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: AaronDot

Documentation/devicetree/bindings/interrupt-controller/loongson,liointc.yaml

@@ -11,8 +11,13 @@ maintainers:
 
 description: |
   This interrupt controller is found in the Loongson-3 family of chips and
-  Loongson-2K1000 chip, as the primary package interrupt controller which
+  Loongson-2K series chips, as the primary package interrupt controller which
   can route local I/O interrupt to interrupt lines of cores.
+  Be aware of the following points.
+  1.The Loongson-2K0500 is a single core CPU;
+  2.The Loongson-2K0500/2K1000 has 64 device interrupt sources as inputs, so we
+    need to define two nodes in dts{i} to describe the "0-31" and "32-61" interrupt
+    sources respectively.
 
 allOf:
   - $ref: /schemas/interrupt-controller.yaml#
@@ -33,6 +38,7 @@ properties:
       - const: main
       - const: isr0
       - const: isr1
+    minItems: 2
 
   interrupt-controller: true
 
@@ -86,7 +92,8 @@ if:
 then:
   properties:
     reg:
-      minItems: 3
+      minItems: 2
+      maxItems: 3
 
   required:
     - reg-names