Merge remote-tracking branch 'remotes/kraxel/tags/usb-20200928-pull-request' into...

usb: xhci sysbus support.
usb: use lock guards.

# gpg: Signature made Mon 28 Sep 2020 14:16:22 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-20200928-pull-request:
  hw/usb: Use lock guard macros
  usb: hcd-xhci-sysbus: Attach xhci to sysbus device
  usb/hcd-xhci: Split pci wrapper for xhci base model
  usb/hcd-xhci: Move qemu-xhci device to hcd-xhci-pci.c
  usb/hcd-xhci: Make dma read/writes hooks pci free

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>