Avoid using the name "pid_t", which is used on unixoid systems.

Avoid using the name "pid_t", which is used on unixoid systems.
Move controller specific data structures into private headers,
to avoid conflicts between controller drivers.
Factor out the USB PID ids, which are only exposed on UHCI. It's
of not much use on the other controllers.

Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de>
Acked-by: Stefan Reinauer <stepan@coresystems.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5616 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1