pci: pcie_dw_meson: fix usb fail when pci link fails to go up

pci: pcie_dw_meson: fix usb fail when pci link fails to go up

On Amlogic A311D, when the PCIe link fails disabling the related clocks
makes USB fail. For an unknown reason, this doesn happen on the S905D3 SoC.

Mimic the Linux behavior by not considering a link failure a probe failure,
and continue even if the PCIe link is down.

Reported-by: Art Nikpal <email2tema@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>