machine: Eliminate unnecessary stringify() usage

machine: Eliminate unnecessary stringify() usage

stringify() is useful when we need to use macros in compat_props
(like when we set virtio-baloon-pci.class=PCI_CLASS_MEMORY_RAM at
pc_i440fx_1_0_machine_options()), but it is pointless when we are
already providing a number literal.

Replace stringify() with string literals when appropriate.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190107193020.21744-3-ehabkost@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>