arm64: dts: qcom: sm8250: add missing qcom,smmu-500 fallback

arm64: dts: qcom: sm8250: add missing qcom,smmu-500 fallback

Since commit 6c84bbd103d8 ("dt-bindings: arm-smmu: Add generic
qcom,smmu-500 bindings") the SMMU is supposed to use qcom,smmu-500
compatible fallback:

  ['qcom,sm8250-smmu-500', 'qcom,adreno-smmu', 'qcom,smmu-500', 'arm,mmu-500'] is too long
  'qcom,sm8250-smmu-500' is not one of ['qcom,msm8996-smmu-v2', 'qcom,msm8998-smmu-v2', 'qcom,sdm630-smmu-v2']
  'qcom,sm8250-smmu-500' is not one of ['qcom,msm8996-smmu-v2', 'qcom,sc7180-smmu-v2', 'qcom,sdm630-smmu-v2', 'qcom,sdm845-smmu-v2'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230416123730.300863-4-krzysztof.kozlowski@linaro.org