usbdebug: Split endpoint buffers

Refactor the structure to better support receive and another
set of endpoints over usbdebug.

Change-Id: Ib0f76afdf4e638363ff30c67010920142c58f250
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3726
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
2 files changed