usb: gadget: printer: SS+ support

commit fd80731e

 upstream.

We need to treat super speed plus as super speed, not the default,
which is full speed.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20240620093800.28901-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>