usbdebug: Reference endpoints by pipes in calls

Add allocation for endpoint0 as a pipe for control messages.

Endpoint number was already stored in the pipe object, place devnum
there too, although all pipes will use same devnum==127.

Change-Id: I299d139bdd8083af8b04a694e8e41435ec026a25
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3864
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
1 file changed