Shows the port speed protocol speed ID (PSID) in use.
speed ID may map to custom speeds, but in most cases it uses default

1 = Full-Speed        12 MB/s
2 = Low-Speed         1.5 Mb/s
3 = High-speed        480 Mb/s
4 = SuperSpeed        5 Gb/s
5 = SuperSpeedPlus    10 Gb/s
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>