hdata/memory.c: Fix "Inconsistent MSAREA" warnings
hdata/memory.c: Fix "Inconsistent MSAREA" warnings

add_memory_buffer_mmio() should be exclusive to P9P (AXONE).
Running it on non P9P systems resulted in warnings such as:

MS AREA: Inconsistent MSAREA version 40 for P9P system

So check for PVR and quietly return if not P9P.

Fixes: 38b5c3179 (Add support for memory-buffer mmio)
Cc: 74fabe089ecbd0f3f71683991d9e2780a4de1f4a@lists.ozlabs.org
Cc: Oliver O'Halloran <3dfaff8fa6ae977f042064a112a6aac576279b9b@gmail.com>
Signed-off-by: Klaus Heinrich Kiwi <d568b8cd7ef64877891488bb3328757d2d21c847@linux.vnet.ibm.com>
Signed-off-by: Oliver O'Halloran <3dfaff8fa6ae977f042064a112a6aac576279b9b@gmail.com>

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