arm64: dts: qcom: sa8775p: Add ep pcie0 controller node

Add ep pcie dtsi node for pcie0 controller found on sa8775p platform.
It supports gen4 and x2 link width. Limiting the speed to Gen3 due to
stability issues.

Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1714492540-15419-4-git-send-email-quic_msarkar@quicinc.com


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