dt-bindings: arm: qcom: Document sm7225 and fairphone,fp4 board

Add binding documentation for Fairphone 4 smartphone which is based on
Snapdragon 750G (sm7225).
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211007212444.328034-10-luca@z3ntu.xyz

Documentation/devicetree/bindings/arm/qcom.yaml

@@ -44,6 +44,7 @@ description: |
         sdm660
         sdm845
         sdx55
+        sm7225
         sm8150
         sm8250
         sm8350
@@ -217,6 +218,11 @@ properties:
               - qcom,sa8155p-adp
           - const: qcom,sa8155p
 
+      - items:
+          - enum:
+              - fairphone,fp4
+          - const: qcom,sm7225
+
       - items:
           - enum:
               - qcom,sm8150-mtp