build: Remove dependency of user space stack cookies from kernel

Currently the user space stack cookies work well also when the kernel
stack cookies are not activated. This is handled completely in user
space and does not need kernel support.

This dependency was probably needed some years ago when the libc did not
support stack cookies.

Reviewed-by: Ian Cooper <iancooper@hotmail.com>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>