dt-bindings: arm: qcom: Document SM8450 HDK boards

Document the SM8450 HDK board
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220203090031.3128702-1-vkoul@kernel.org

Documentation/devicetree/bindings/arm/qcom.yaml

@@ -268,6 +268,7 @@ properties:
 
       - items:
           - enum:
+              - qcom,sm8450-hdk
               - qcom,sm8450-qrd
           - const: qcom,sm8450