There's no reason to keep the property list separate from the CPU
class code.  Move the variable to hw/core/cpu.c and make it
static.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20201211220529.2290218-3-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>