usb: bugfixes and minor improvements.
# gpg: Signature made Thu 22 Aug 2019 07:52:32 BST
# gpg: using RSA key
4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg: aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg: aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901 FE7D 4CB6 D8EE D3E8 7138
* remotes/kraxel/tags/usb-
20190822-pull-request:
ehci: fix queue->dev null ptr dereference
usb: reword -usb command-line option and mention xHCI
xhci: Add No Op Command
usb-redir: merge interrupt packets
usbredir: fix buffer-overflow on vmload
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>