Merge branch 'pci/controller/dwc-imx6'

Merge branch 'pci/controller/dwc-imx6'

- Add DT binding and driver support for an optional external refclock in
  addition to the refclock from the internal PLL (Richard Zhu)

- Apply i.MX95 ERR051586 erratum workaround (release CLKREQ# so endpoint
  can assert it when required) during resume (Richard Zhu)

- Enable i.MX95 REFCLK by overriding CLKREQ# so it's driven by default
  (Richard Zhu)

- Clear CLKREQ# override if link is up and DT says 'supports-clkreq' so
  endpoints can use CLKREQ# to exit the L1.2 state (Richard Zhu)

* pci/controller/dwc-imx6:
  PCI: imx6: Clear CLKREQ# override if 'supports-clkreq' DT property is available
  PCI: imx6: Add CLKREQ# override to enable REFCLK for i.MX95 PCIe
  PCI: dwc: Invoke post_init in dw_pcie_resume_noirq()
  PCI: imx6: Add external reference clock input mode support
  dt-bindings: PCI: pci-imx6: Add external reference clock input
  dt-bindings: PCI: dwc: Add external reference clock input