usb: show speed "10000" in sysfs for USB 3.1 SuperSpeedPlus devices

The same way as SuperSpeed devices show "5000" as device speed we wan't to
show "10000" as the default speed for SuperSpeedPlus devices in sysfs.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>