arm64: dts: qcom: sa8775p: Mark PCIe EP controller as cache coherent

The PCIe EP controller on SA8775P supports cache coherency, hence add
the "dma-coherent" property to mark it as such.

Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/1710166298-27144-4-git-send-email-quic_msarkar@quicinc.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>