usbip: Use _FORTIFY_SOURCE=2 instead of (implicitly) =1

_FORTIFY_SOURCE=2 uses more and stricter checks. This is what e.g.
Debian recommends to build packages with.

While at it fix a typo in the output of ./configure --help.

Signed-off-by: Uwe Kleine-König <ukleinek@debian.org>
Reviewed-By: Hongren Zheng <i@zenithal.me>
Link: https://lore.kernel.org/r/20230503173622.1072787-1-ukleinek@debian.org


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