qemu_monitor: add features to CPU model for QMP command

qemu_monitor: add features to CPU model for QMP command

query-cpu-model-baseline/comparison will accept a list of features
as part of the command. Since CPUs may be defined with CPU feature
policies, let's parse it to the appropriate boolean that the QMP
command expects.

A feature that is set to required, force, or if it is a hypervisor
CPU feature (-1), then set the property value to true. Otherwise
(optional, disabled) set the value to false.

Signed-off-by: Collin Walling <walling@linux.ibm.com>
Message-Id: <1568924706-2311-5-git-send-email-walling@linux.ibm.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>