usb: core: hub: Remove port_speed_is_ssp()

The get_port_ssp_rate() can replace port_speed_is_ssp(). If the port
speed is detected to be in gen2x1, gen1x2, or gen2x2, then the port is
operating at SuperSpeed Plus.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/dfd61ae637597bad502d2420b4dbd3774fc76aab.1615432770.git.Thinh.Nguyen@synopsys.com


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