Merge remote-tracking branch 'remotes/kraxel/tags/usb-20180227-pull-request' into staging

usb: add mtp write support.

# gpg: Signature made Tue 27 Feb 2018 08:39:01 GMT
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/usb-20180227-pull-request:
  usb-mtp: Advertise SendObjectInfo for write support
  usb-mtp: Introduce write support for MTP objects
  usb-mtp: Support delete of mtp objects
  usb-mtp: print parent path in IN_IGNORED trace fn
  usb-mtp: Add one more argument when building results
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>