usb: dwc3: gadget: Track connected SSP rate and lane count

Track the number of connected lanes and speed in corresponding enum
usb_ssp_rate for SuperSpeed Plus capable device.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/2389592188d2e37a2ee45edaf04d942b19f3af82.1611106162.git.Thinh.Nguyen@synopsys.com


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