powerpc: Define CPU feature for Architected 2.06 HV mode

This bit indicates that we are operating in hypervisor mode on a CPU
compliant to architecture 2.06 or later (currently server only).

We set it on POWER7 and have a boot-time CPU setup function that
clears it if MSR:HV isn't set (booting under a hypervisor).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --cc arch/powerpc/include/asm/cputable.h
Simple merge

diff --cc arch/powerpc/kernel/Makefile
Simple merge

diff --cc arch/powerpc/kernel/cpu_setup_power7.S
Simple merge

diff --cc arch/powerpc/kernel/cputable.c
Simple merge