arm64: dts: qcom: qdu1000: add missing qcom,smmu-500 fallback

Since commit 6c84bbd1 ("dt-bindings: arm-smmu: Add generic
qcom,smmu-500 bindings") the SMMU is supposed to use qcom,smmu-500
compatible fallback:

  ['qcom,qdu1000-smmu-500', 'arm,mmu-500'] is too short
  ['qcom,qdu1000-smmu-500', 'arm,mmu-500'] is too long
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/20230416123730.300863-3-krzysztof.kozlowski@linaro.org

arch/arm64/boot/dts/qcom/qdu1000.dtsi

@@ -1103,7 +1103,7 @@ qup_spi15_cs: qup-spi15-cs-state {
 		};
 
 		apps_smmu: iommu@15000000 {
-			compatible = "qcom,qdu1000-smmu-500", "arm,mmu-500";
+			compatible = "qcom,qdu1000-smmu-500", "qcom,smmu-500", "arm,mmu-500";
 			reg = <0x0 0x15000000 0x0 0x100000>;
 			#iommu-cells = <2>;
 			#global-interrupts = <2>;