dt-bindings: arm: qcom: Document the Qualcomm qrb4210-rb2 board

Document the Qualcomm qrb4210-rb2 board based on Robotics version
of the Snapdragon SM4250 Soc, i.e. QRB4210.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230411072840.2751813-2-bhupesh.sharma@linaro.org

Documentation/devicetree/bindings/arm/qcom.yaml

@@ -50,6 +50,7 @@ description: |
         qcm2290
         qdu1000
         qrb2210
+        qrb4210
         qru1000
         sa8155p
         sa8540p
@@ -97,6 +98,7 @@ description: |
         liquid
         mtp
         qrd
+        rb2
         ride
         sbc
         x100
@@ -874,6 +876,12 @@ properties:
               - oneplus,billie2
           - const: qcom,sm4250
 
+      - items:
+          - enum:
+              - qcom,qrb4210-rb2
+          - const: qcom,qrb4210
+          - const: qcom,sm4250
+
       - items:
           - enum:
               - lenovo,j606f