powerpc/smp: Add a smp_ops->bringup_up() done callback

This allows us to stop abusing smp_ops->setup_cpu() for cleanup
tasks that have to take place after the initial boot time CPU
bringup.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 578d330..e4f0191 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -35,6 +35,7 @@
 	int   (*probe)(void);
 	void  (*kick_cpu)(int nr);
 	void  (*setup_cpu)(int nr);
+	void  (*bringup_done)(void);
 	void  (*take_timebase)(void);
 	void  (*give_timebase)(void);
 	int   (*cpu_disable)(void);