The i.MX SoCs have various clock configurations routed into the PCIe IP,
the list of clock is below. Document all those configurations in the DT
binding document.

All SoCs: pcie, pcie_bus
6QDL, 7D: + pcie_phy
6SX:      + pcie_phy          pcie_inbound_axi
8MQ:      + pcie_phy pcie_aux
8MM, 8MP: +          pcie_aux
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20221211024859.672076-1-marex@denx.deSigned-off-by: Rob Herring <robh@kernel.org>