Patch merged into coreboot/master: libpayload: usb: dwc2: fix usb plug/unplug bug

the following patch was just integrated into master:
commit 4938426783423889717e67f6be85e360a5f02d95
Author: Yunzhi Li 
Date:   Tue Aug 11 17:58:14 2015 +0800

libpayload: usb: dwc2: fix usb plug/unplug bug

Check device connect status while waiting for usb transfer complete
    Avoid coreboot get stuck when usb device unplugged

BUG=chrome-os-partner:35525
    TEST=None
    BRANCH=None

Original-Change-Id: Id103501aa0d8b31b0b81bef773679c0fad79f689
    Original-Signed-off-by: Yunzhi Li 
    Original-Reviewed-on: https://chromium-review.googlesource.com/292630
    Original-Reviewed-by: Patrick Georgi 
    Original-Reviewed-by: Julius Werner 
    Original-Commit-Queue: Lin Huang 
    Original-Tested-by: Lin Huang 
    Original-Reviewed-on: https://chromium-review.googlesource.com/292966
    Original-Reviewed-by: David Hendricks 
    Original-Tested-by: David Hendricks 
    Original-Commit-Queue: David Hendricks

Change-Id: I49396b74131dbfda505d9d3de5adbdc87eb92ce1
    Signed-off-by: Yunzhi Li 
    Reviewed-on: http://review.coreboot.org/11236
    Tested-by: build bot (Jenkins)
    Reviewed-by: Stefan Reinauer

See http://review.coreboot.org/11236 for details.

-gerrit