ARM: dts: qcom: sdx55: Add Qcom SMMU-500 as the fallback for IOMMU node

SDX55 uses the Qcom version of the SMMU-500 IP. So use "qcom,smmu-500"
compatible as the fallback to the SoC specific compatible.

Cc: <[e-mail]> # 5.12
Fixes: a2bdfdfba2af ("ARM: dts: qcom: sdx55: Enable ARM SMMU")
Signed-off-by: Manivannan Sadhasivam <[e-mail]>
Reviewed-by: Konrad Dybcio <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/arm/boot/dts/qcom-sdx55.dtsi

···
 		};
 
 		apps_smmu: iommu@15000000 {
-			compatible = "qcom,sdx55-smmu-500", "arm,mmu-500";
+			compatible = "qcom,sdx55-smmu-500", "qcom,smmu-500", "arm,mmu-500";
 			reg = <0x15000000 0x20000>;
 			#iommu-cells = <2>;
 			#global-interrupts = <1>;