rust: chardev, qdev: add bindings to qdev_prop_set_chr

Because the argument to the function is an Owned<Chardev>, this also
adds an ObjectType implementation to Chardev.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust/qemu-api/meson.build

@@ -20,6 +20,7 @@ _qemu_api_rs = static_library(
       'src/bitops.rs',
       'src/callbacks.rs',
       'src/cell.rs',
+      'src/chardev.rs',
       'src/c_str.rs',
       'src/irq.rs',
       'src/memory.rs',