ALSA: virtio: use module_virtio_driver() to simplify the code

module_virtio_driver() makes the code simpler by eliminating
boilerplate code.
Signed-off-by: Chen Huang <chenhuang5@huawei.com>
Reviewed-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210408125429.1158703-1-chenhuang5@huawei.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/virtio/virtio_card.c

@@ -432,17 +432,7 @@ static struct virtio_driver virtsnd_driver = {
 #endif
 };
 
-static int __init init(void)
-{
-	return register_virtio_driver(&virtsnd_driver);
-}
-module_init(init);
-
-static void __exit fini(void)
-{
-	unregister_virtio_driver(&virtsnd_driver);
-}
-module_exit(fini);
+module_virtio_driver(virtsnd_driver);
 
 MODULE_DEVICE_TABLE(virtio, id_table);
 MODULE_DESCRIPTION("Virtio sound card driver");