PCI: qcom: Add support for SC8280XP

PCI: qcom: Add support for SC8280XP

The SC8280XP platform has seven PCIe controllers: two used with USB4,
two 4-lane, two 2-lane and one 1-lane.

Add a new "qcom,pcie-sc8280xp" compatible string and reuse the 1.9.0
ops.

Note that the SC8280XP controllers need two or three interconnect
clocks to be enabled. Model these as optional clocks to avoid encoding
devicetree data in the PCIe driver.

Note that the same could be done for the SM8450 interconnect clocks and
possibly also for the TBU clocks.

Link: https://lore.kernel.org/r/20220714071348.6792-5-johan+linaro@kernel.org
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>