target-ppc: move POWER7+ to a separate family

target-ppc: move POWER7+ to a separate family

So far POWER7+ was a part of POWER7 family. However it has a different
PVR base value so in order to support PVR masks, it needs a separate
family class.

This adds a new family class, PVR base and mask values and moves
Power7+ v2.1 CPU to a new family. The class init function is copied
from the POWER7 family.

This defines a firmware name for the new family as "PowerPC,POWER7+"
instead of previously used "PowerPC,POWER7" from the POWER7 family.
The reason for that is that the Sapphire firmware (a h0st firmware)
uses "PowerPC,POWER7+" already and since no specification defines
exactly the CPU nodes naming in the device tree, we better stay
in sync with the host firmware.

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