usb: xhci: Init root hub SSP rate

Initialize USB 3.x root hub SuperSpeed Plus rate.

Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/f1698a96d5f9dfaefb857b95e5db6135ae0c9e93.1615432770.git.Thinh.Nguyen@synopsys.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>