powerpc: move a stray NMI IPI case under NMI_IPI ifdef

Signed-off-by: Nicholas Piggin <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/kernel/smp.c

···
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 	[PPC_MSG_TICK_BROADCAST] = "ipi tick-broadcast",
 #endif
+#ifdef CONFIG_NMI_IPI
 	[PPC_MSG_NMI_IPI] = "nmi ipi",
+#endif
 };
 
 /* optional function to request ipi, for controllers with >= 4 ipis */