KVM: x86 emulator: emulate CLTS internally

Avoid using ctxt->vcpu; we can do everything with ->get_cr() and ->set_cr().

A side effect is that we no longer activate the fpu on emulated CLTS; but that
should be very rare.

Signed-off-by: Avi Kivity <avi@redhat.com>

diff --cc arch/x86/include/asm/kvm_host.h
Simple merge

diff --cc arch/x86/kvm/emulate.c
Simple merge

diff --cc arch/x86/kvm/x86.c
Simple merge