usb: ch9: Add USB 3.2 SSP attributes

In preparation for USB 3.2 dual-lane support, add sublink speed
attribute macros and enum usb_ssp_rate. A USB device that operates in
SuperSpeed Plus may operate at different speed and lane count. These
additional macros and enum values help specifying that.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/ae9293ebd63a29f2a2035054753534d9eb123d74.1610592135.git.Thinh.Nguyen@synopsys.com


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