SLW: Fix mambo boot to use stop states

After commit 35c66b8 ("SLW: Move MAMBO simulator checks to
slw_init"), mambo boot no longer calls add_cpu_idle_state_properties()
and as such we never enable stop states.

After adding the call back, we get more testing coverage as well
as faster mambo SMT boots.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

hw/slw.c

@@ -1581,6 +1581,7 @@ void slw_init(void)
 
 	if (proc_chip_quirks & QUIRK_MAMBO_CALLOUTS) {
 		wakeup_engine_state = WAKEUP_ENGINE_NOT_PRESENT;
+		add_cpu_idle_state_properties();
 		return;
 	}
 	if (proc_gen == proc_gen_p8) {