target-ppc: Add support for POWER8 pvr 0x4D0000

target-ppc: Add support for POWER8 pvr 0x4D0000

At the moment QEMU knows about one version of POWER8 CPU with
PVR 0x4B.0000. This CPU class is defined as "POWER8". The linux
kernel names it as "POWER8E" which is different from the name QEMU uses.

Now we get another version of POWER8 which is architecturally equivalent
to POWER8E but has different PVR 0x4D.0000 so QEMU fails to find
a PPC CPU class on these machines. The linux kernel names these CPUs as
"POWER8".

This renames the existing "POWER8" to "POWER8E" to be more precise and
stay in sync with the linux kernel.

This adds a new "POWER8" family which calls POWER8E class init function
and defines own PVR mask (used to match a CPU class) and desc (used to
create dynamic version-less CPU class).

This does not change CPU class fw_name attribute as the host POWER8
firmware keeps using "PowerPC,POWER8" on both POWER8 and POWER8E.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>