external/mambo: add device tree fixup for POWER9 stop levels
external/mambo: add device tree fixup for POWER9 stop levels

Signed-off-by: Nicholas Piggin <24829078df5003d9dd1dd871ca2aeb0b1cf95ef4@gmail.com>
Reviewed-by: Vaidyanathan Srinivasan <c012decff9dffda4c10860ab2ba9eb53320d90bc@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

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