hw/dts: retry special wakeup operation if core still gated
hw/dts: retry special wakeup operation if core still gated

It has been observed that in some cases the special wakeup
operation can "succeed" but the core is still in a gated/offline
state.

Check for this state after attempting to wakeup a core and retry
the wakeup if necessary.

Change-Id: Ia6b1b75dcab590c299bed3ee0a42031f09c39eda
Signed-off-by: Robert Lippert <c065cdb6ddd7bea176bf96c0c5ae92b2a677c1e0@google.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

shenki/skiboot,open-power/skiboot,legoater/skiboot,stewart-ibm/skiboot,legoater/skiboot,open-power/skiboot,qemu/skiboot,qemu/skiboot,legoater/skiboot,shenki/skiboot,stewart-ibm/skiboot,qemu/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot,shenki/skiboot,legoater/skiboot,stewart-ibm/skiboot,shenki/skiboot,open-power/skiboot,qemu/skiboot