dt-bindings: crypto: qcom,prng: document that RNG on SM8450 is a TRNG

It has been reported at [1] the RNG HW on SM8450 is in fact a True Random
Number Generator and no more Pseudo, document this by adding
a new qcom,trng and the corresponding SoC specific sm8450 compatible.

[1] https://lore.kernel.org/all/20230818161720.3644424-1-quic_omprsing@quicinc.com/Suggested-by: Om Prakash Singh <quic_omprsing@quicinc.com>
Suggested-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Om Prakash Singh <quic_omprsing@quicinc.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Documentation/devicetree/bindings/crypto/qcom,prng.yaml

@@ -11,9 +11,14 @@ maintainers:
 
 properties:
   compatible:
-    enum:
-      - qcom,prng  # 8916 etc.
-      - qcom,prng-ee  # 8996 and later using EE
+    oneOf:
+      - enum:
+          - qcom,prng  # 8916 etc.
+          - qcom,prng-ee  # 8996 and later using EE
+      - items:
+          - enum:
+              - qcom,sm8450-trng
+          - const: qcom,trng
 
   reg:
     maxItems: 1
@@ -28,8 +33,18 @@ properties:
 required:
   - compatible
   - reg
-  - clocks
-  - clock-names
+
+allOf:
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              const: qcom,trng
+    then:
+      required:
+        - clocks
+        - clock-names
 
 additionalProperties: false