KVM: PPC: Book3S HV: Fix KVM hang with CONFIG_KVM_XICS=n

I noticed KVM is broken when KVM in-kernel XICS emulation
(CONFIG_KVM_XICS) is disabled.

The problem was introduced in 48eaef05

 (KVM: PPC: Book3S HV: use
xics_wake_cpu only when defined). It used CONFIG_KVM_XICS to wrap
xics_wake_cpu, where CONFIG_PPC_ICP_NATIVE should have been
used.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>