[PATCH] x86-64: Fix ENOSYS in system call tracing

This patch:

- out of range system calls failing to return -ENOSYS under
  system call tracing

[AK: split out from another patch by Jan as separate bugfix]

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>