usb: gadget: composite: Use SSP sublink speed macros

Use SuperSpeed Plus sublink speed macros to fill the BOS descriptor
sublink speed attributes in the composite driver. They're
self-documented so we can remove some of the comments, and this helps
with readability by removing the magic numbers.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/6f74d446aa164f66fbe4161e28547e28851f6a02.1610592135.git.Thinh.Nguyen@synopsys.com


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