Merge remote-tracking branch 'remotes/kraxel/tags/usb-20201104-pull-request' into...

usb: bugfixes for usb-serial

# gpg: Signature made Wed 04 Nov 2020 12:13:05 GMT
# 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-20201104-pull-request:
  dev-serial: store flow control and xon/xoff characters
  dev-serial: add support for setting data_bits in QEMUSerialSetParams
  dev-serial: add always-plugged property to ensure USB device is always attached
  dev-serial: replace DeviceOutVendor/DeviceInVendor with equivalent macros from usb.h
  dev-serial: add trace-events for baud rate and data parameters
  dev-serial: convert from DPRINTF to trace-events
  dev-serial: use USB_SERIAL QOM macro for USBSerialState assignments
  dev-serial: style changes to improve readability and checkpatch fixes

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