arm64: dts: qcom: sc7280: Mark PCIe controller as cache coherent

In the Linux kernel, the following vulnerability has been resolved: arm64: dts: qcom: sc7280: Mark PCIe controller as cache coherent If the controller is not marked as cache coherent, then kernel will try to ensure coherency during dma-ops and that may cause data corruption. So, mark the PCIe node as dma-coherent as the devices on PCIe bus are cache coherent.