dt-bindings: misc: qcom,fastrpc: restrict channel names

The Qualcomm FastRPC is expected to in GLINK or SMD edge node and its
channel name is always the same.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220909125403.803158-4-krzysztof.kozlowski@linaro.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/misc/qcom,fastrpc.yaml

@@ -32,7 +32,8 @@ properties:
       A list of channels tied to this function, used for matching
       the function to a set of virtual channels.
     $ref: "/schemas/types.yaml#/definitions/string-array"
-    maxItems: 1
+    items:
+      - const: fastrpcglink-apps-dsp
 
   qcom,non-secure-domain:
     description:
@@ -43,7 +44,8 @@ properties:
     description:
       Channel name used for the RPM communication
     $ref: "/schemas/types.yaml#/definitions/string-array"
-    maxItems: 1
+    items:
+      - const: fastrpcsmd-apps-dsp
 
   qcom,vmids:
     description: