xHCI's PCI fixup, run at the end of pcie-brcmstb's probe, depends on
RPi4's VideoCore firmware interface to be up and running. It's possible
for both initializations to race, so make sure it's available prior
starting.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>[...]
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>