ALSA: pci: clean up using module_pci_driver()

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/oxygen/virtuoso.c b/sound/pci/oxygen/virtuoso.c
index 3fdee49..19962c6 100644
--- a/sound/pci/oxygen/virtuoso.c
+++ b/sound/pci/oxygen/virtuoso.c
@@ -100,15 +100,4 @@
 	.shutdown = oxygen_pci_shutdown,
 };
 
-static int __init alsa_card_xonar_init(void)
-{
-	return pci_register_driver(&xonar_driver);
-}
-
-static void __exit alsa_card_xonar_exit(void)
-{
-	pci_unregister_driver(&xonar_driver);
-}
-
-module_init(alsa_card_xonar_init)
-module_exit(alsa_card_xonar_exit)
+module_pci_driver(xonar_driver);