qdev: show name of device that fails init

When initialising a device fails, show the name of the failing device.

The current behaviour is to silently exit on such errors.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/qdev.c

@@ -215,6 +215,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
         return NULL;
     }
     if (qdev_init(qdev) != 0) {
+        qemu_error("Error initializing device %s\n", driver);
         qdev_free(qdev);
         return NULL;
     }