virtio-snd: check AUD_register_card return value

AUD_register_card might fail. Even though errp was passed as an
argument, the call's return value was not checked for failure.

Fixes: Coverity CID 1523899
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20231109162034.2108018-1-manos.pitsidianakis@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/audio/virtio-snd.c

@@ -1102,7 +1102,9 @@ static void virtio_snd_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    AUD_register_card("virtio-sound", &vsnd->card, errp);
+    if (!AUD_register_card("virtio-sound", &vsnd->card, errp)) {
+        return;
+    }
 
     /* set default params for all streams */
     default_params.features = 0;