In preparation for having other callers of the seccomp mode setting
logic, split the prctl entry point away from the core logic that performs
seccomp mode setting.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Reviewed-by: NAndy Lutomirski <luto@amacapital.net>