Merge remote-tracking branch 'remotes/kraxel/tags/usb-20210729-pull-request' into...

usb: fixes for 6.1: usbredir, usb-host for windows, docs.

# gpg: Signature made Thu 29 Jul 2021 13:50:32 BST
# gpg:                using RSA key A0328CFFB93A17A79901FE7D4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <[email protected]>" [full]
# gpg:                 aka "Gerd Hoffmann <[email protected]>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <[email protected]>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/usb-20210729-pull-request:
  docs: Fold usb2.txt passthrough information into usb.rst
  docs: Fold usb2.txt physical port addressing info into usb.rst
  docs: Fold usb2.txt USB controller information into usb.rst
  docs: Incorporate information in usb-storage.txt into rST manual
  usbredir: fix free call
  ci: add libusb for windows builds
  usb-host: wire up timer for windows

Signed-off-by: Peter Maydell <[email protected]>