ALSA: Fix invalid __exit in sound/mips/*.c

The remove callback has to be marked as __devexit, as the dynamic unbind
is possible.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/mips/sgio2audio.c b/sound/mips/sgio2audio.c
index e497525..8691f4c 100644
--- a/sound/mips/sgio2audio.c
+++ b/sound/mips/sgio2audio.c
@@ -973,7 +973,7 @@
 	return 0;
 }
 
-static int __exit snd_sgio2audio_remove(struct platform_device *pdev)
+static int __devexit snd_sgio2audio_remove(struct platform_device *pdev)
 {
 	struct snd_card *card = platform_get_drvdata(pdev);