[POWERPC] check firmware state before suspending

Currently the kernel blindly halts all the processors and calls the
ibm,suspend-me rtas call.  If the firmware is not in the correct
state, we then re-start all the processors and return.  It is much
smarter to first check the firmware state, and only if it is waiting,
call the ibm,suspend-me call.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/rtas.h b/include/asm-powerpc/rtas.h
index a3b4e55..02e213e 100644
--- a/include/asm-powerpc/rtas.h
+++ b/include/asm-powerpc/rtas.h
@@ -24,6 +24,7 @@
 #define RTAS_RMOBUF_MAX (64 * 1024)
 
 /* RTAS return status codes */
+#define RTAS_NOT_SUSPENDABLE	-9004
 #define RTAS_BUSY		-2    /* RTAS Busy */
 #define RTAS_EXTENDED_DELAY_MIN	9900
 #define RTAS_EXTENDED_DELAY_MAX	9905