hw/nx: Enable p10 DARN
hw/nx: Enable p10 DARN

Init and enable NCU DARN BAR on sibling cores as well for fused core mode.

Signed-off-by: Ryan Grimm <b82eecdfce19ef6c0125840b498d3afc6226dd31@linux.ibm.com>
Signed-off-by: Vaidyanathan Srinivasan <c012decff9dffda4c10860ab2ba9eb53320d90bc@linux.ibm.com>
[Folded Vaidy's fused core support fix - Vasant]
Signed-off-by: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>

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