Intel manual (and KVM definition) say the TPR is 4 bits wide.  Also fix
CR8_RESEVED_BITS typo.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>