rust: rename qemu-api modules to follow C code a bit more

A full match would mean calling them qom::object and hw::core::qdev.  For now,
keep the names shorter but still a bit easier to find.

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

rust/qemu-api/src/sysbus.rs

@@ -9,9 +9,9 @@ pub use bindings::{SysBusDevice, SysBusDeviceClass};
 use crate::{
     bindings::{self, DeviceClass},
     cell::bql_locked,
-    definitions::ClassInitImpl,
     irq::InterruptSource,
     prelude::*,
+    qom::ClassInitImpl,
 };
 
 unsafe impl ObjectType for SysBusDevice {