module: Rename machine_init() to opts_init()

The only remaining users of machine_init() only call
qemu_add_opts(). Rename machine_init() to opts_init() and move it
closer to the qemu_add_opts() calls on vl.c.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
diff --git a/fsdev/qemu-fsdev-opts.c b/fsdev/qemu-fsdev-opts.c
index 0b4619f..88a4ac3 100644
--- a/fsdev/qemu-fsdev-opts.c
+++ b/fsdev/qemu-fsdev-opts.c
@@ -83,4 +83,4 @@
     qemu_add_opts(&qemu_fsdev_opts);
     qemu_add_opts(&qemu_virtfs_opts);
 }
-machine_init(fsdev_register_config);
+opts_init(fsdev_register_config);