dt-bindings: PCI: qcom-ep: Add support for SA8775P SoC

Add devicetree bindings support for SA8775P SoC. It has DMA register
space and dma interrupt to support HDMA.

Link: https://lore.kernel.org/linux-pci/1714492540-15419-2-git-send-email-quic_msarkar@quicinc.com


Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>