usbdebug: Add option for verbose logging of connection

Add option to log changes in USB 2.0 EHCI debug port connection.
For romstage move usbdebug as the last initialised console so one
actually can see these messages.

Init order of consoles in ramstage is undetermined and unchanged.

Change-Id: I3aceec8a93064bd952886839569e9f5beb6c5720
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3387
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
3 files changed