We'll use this property in a follow-up patch to insantiate an EHCI
bus with companion support.
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-id: 20200217204812.9857-3-linux@roeck-us.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>