hw/usb: pacify xhciwmi.exe warning

hw/usb: pacify xhciwmi.exe warning

xhciwmi.exe is used inside Windows 2022 SVVP tests. This tool called as
'xhciwmi.exe --verify' reports that 'The firmware loaded on this
controller has known bugs and/or compatibility issues'. This is just
a warning but there is no particular sense to ignore it.

This patch just pacifies the tool.

There is a big question whether this change should be put using
machine type mechanics, but at my opinion this would be an overkill.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Tested-by: Pavel Polozov <pavel.polozov@virtuozzo.com>
CC: Yan Vugenfirer <yvugenfi@redhat.com>
CC: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Yan Vugenfirer <yvugenfi@redhat.com>
Message-Id: <20211223095443.130276-1-den@openvz.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>