libpayload: usb: xhci: Support rockchip xHCI controller

1. Make the xHCI driver to support xHCI controller v1.1
2. And a new function xhci_ring_doorbell(), it aims to
   add a memory barrier before ringing the doorbell, to ensure
   all TRB changes are written to memory.

BRANCH=none
BUG=chrome-os-partner:52684
TEST=boot from USB on Kevin rk3399 platform

Change-Id: Ife1070d1265476d0f5b88e2acf3299fc84af5832
Signed-off-by: Martin Roth <martinroth@chromium.org>
Original-Commit-Id: 0c21e92
Original-Change-Id: I4e38e04dc3c7d32ee4bb424a473c70956a3c3ea9
Original-Signed-off-by: Liangfeng Wu <wulf@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/346831
Original-Commit-Ready: Brian Norris <briannorris@chromium.org>
Original-Tested-by: Douglas Anderson <dianders@chromium.org>
Original-Reviewed-by: Douglas Anderson <dianders@chromium.org>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/15111
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
2 files changed