Add initial PCIe support for the imx6 SoC derivate imx6sx. PCI MSI support
is untested as the necessary suspend/resume quirk is not included in this
patch.
This patch is heavily based on patches by Richard Zhu.
[bhelgaas: factor out refclk enable, fix adjacent typos in imx6q-pcie.txt] Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com> Acked-by: Richard Zhu <Richard.Zhu@freescale.com> Acked-by: Lucas Stach <l.stach@pengutronix.de>