PCI: qcom-ep: Add support for SA8775P SOC

PCI: qcom-ep: Add support for SA8775P SOC

Add support for SA8775P SoC to the Qualcomm PCIe Endpoint Controller
driver. Adding new compatible string as it has different set of clocks
compared to other SoCs.

Link: https://lore.kernel.org/linux-pci/1714492540-15419-3-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: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>