Platform/RaspberryPi: Ensure USB controller init before console

Due to the nature of USB init on the Pi platforms, commit
c8000ecc introduced a regression
with regards to ensuring that USB devices are operational by the
time the console is up.

This commit fixes this by adding explicit calls to connect USB
controllers before console initialization.

Note that trying to connect a non existent device (e.g. PCI bus
on the Pi 3) is harmless so there's no need to guard these calls
according to the devices effectively supported by the platform.

Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>