usb: usb-skeleton: make comment block in line with coding style

Comment block was not in accordance with coding style.
Fixes two checkpatch warnings:
WARNING: Block comments use * on subsequent lines
WARNING: Block comments use a trailing */ on a separate line

Signed-off-by: Jacob Huisman <jacobhuisman@kernelthusiast.com>
Link: https://lore.kernel.org/r/20190815174210.580-1-jacobhuisman@kernelthusiast.com


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