PCI: qcom: Add support for ddrss_sf_tbu clock

PCI: qcom: Add support for ddrss_sf_tbu clock

On SM8250 additional clock is required for PCIe devices to access NOC.
Update PCIe controller driver to control this clock.

Link: https://lore.kernel.org/r/20210117013114.441973-3-dmitry.baryshkov@linaro.org
Fixes: e1dd639e374a ("PCI: qcom: Add SM8250 SoC support")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>