[IA64] Wire up kcmp syscall

[IA64] Wire up kcmp syscall

systemd > 218 fails to compile on ia64 with:

     error: ‘__NR_kcmp’ undeclared [1].

I've been told that this is because the kcmp syscall hasn't been wired up
for the ia64 arch [2].

The proposed patch thus wire up the kcmp syscall for the ia64 arch.

[1] https://bugs.gentoo.org/show_bug.cgi?id=560492
[2] https://bugs.gentoo.org/show_bug.cgi?id=560492#c17

Signed-off-by: Émeric MASCHINO <emeric.maschino@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>