Patch merged into coreboot/master: libpayload: usb: dwc2: support interrupt transfer

the following patch was just integrated into master:
commit aa33609d289c4ee07ec10e4825bc055492fa107c
Author: Yunzhi Li 
Date:   Fri Jun 19 17:09:04 2015 +0800

libpayload: usb: dwc2: support interrupt transfer

dwc2 host core do not have a periodic schedule list, so try to send
    an interrupt packet in poll_intr_queue() function and use frame
    number read from usb core register to calculate time and schedule
    transfers.

BUG=None
    TEST=Tested on RK3288 with two USB keyboards(connect to SoC without
    USB hub), both work correctly.
    BRANCH=None

Change-Id: I16f7977c45a84b37c32b7c495ca78ad76be9f0ce
    Signed-off-by: Patrick Georgi 
    Original-Commit-Id: 3d0206b86634bcfdbe03da3e2c8adf186470e157
    Original-Change-Id: Ie54699162ef799f4d3d2a0abf850dbeb62417777
    Original-Signed-off-by: Yunzhi Li 
    Original-Reviewed-on: https://chromium-review.googlesource.com/280750
    Original-Reviewed-by: Julius Werner 
    Original-Commit-Queue: Lin Huang 
    Original-Tested-by: Lin Huang 
    Reviewed-on: http://review.coreboot.org/10774
    Tested-by: build bot (Jenkins)
    Reviewed-by: Stefan Reinauer

See http://review.coreboot.org/10774 for details.

-gerrit