Patch merged into coreboot/master: c080577 libpayload: Implement usb_exit

the following patch was just integrated into master:
commit c0805779c25bb3819eb9d244fdfd7d7ca894516f
Author: Patrick Georgi 
Date:   Fri Nov 4 12:06:06 2011 +0100

libpayload: Implement usb_exit

So far it was empty and never published. It now exists and shuts down
    all controllers (esp. EHCI which resets the port routers).

Change-Id: I81e355e8a05778d6397675417b085a094a6f48ee
    Signed-off-by: Patrick Georgi

Build-Tested: build bot (Jenkins) at Fri Nov  4 22:01:20 2011, giving +1
Reviewed-By: Stefan Reinauer  at Fri Nov  4 22:14:17 2011, giving +2
See http://review.coreboot.org/397 for details.

-gerrit