xhci: USB 3.1 add default Speed Attributes to SuperSpeedPlus device capability

If a xhci controller does not provide a protocol speed ID (PSI) table, a
default one should be used instead. Add the default values to the
SuperSpeedPlus device capability. Overwrite the default ones if a PSI table
exists. See xHCI 1.1 sectio 7.2.2.1.1 for more info

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