KVM: implement multiple address spaces

Only two ioctls have to be modified; the address space id is
placed in the higher 16 bits of their slot id argument.

As of this patch, no architecture defines more than one
address space; x86 will be the first.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --cc Documentation/virtual/kvm/api.txt
Simple merge

diff --cc arch/powerpc/include/asm/kvm_book3s_64.h
Simple merge

diff --cc include/linux/kvm_host.h
Simple merge

diff --cc include/uapi/linux/kvm.h
Simple merge

diff --cc virt/kvm/kvm_main.c
Simple merge