[POWERPC] powermac: Suspend to disk on G5

Powermac G5 suspend to disk implementation.  The code is platform
agnostic but only tested on powermac, no other 64-bit powerpc
machines.

Because nvidiafb still breaks suspend I have marked it EXPERIMENTAL on
powermac and because I can't test it and some lowlevel code will need
changes it is BROKEN on all other 64-bit platforms.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 6e7f509..a9e9cbd 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -33,8 +33,11 @@
 #include <asm/smp.h>
 
 #ifdef CONFIG_HOTPLUG_CPU
+/* this is used for software suspend, and that shuts down
+ * CPUs even while the system is still booting... */
 #define cpu_should_die()	(cpu_is_offline(smp_processor_id()) && \
-				 system_state == SYSTEM_RUNNING)
+				   (system_state == SYSTEM_RUNNING     \
+				 || system_state == SYSTEM_BOOTING))
 #else
 #define cpu_should_die()	0
 #endif