ALSA: mips/hal2: Remove redundant platform_set_drvdata()

Commit 0998d06310 (device-core: Ensure drvdata = NULL when no
driver is bound) removes the need to set driver data field to
NULL.

Signed-off-by: Sachin Kamat <[e-mail]>
Cc: Thomas Bogendoerfer <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

sound/mips/hal2.c

···
 	struct snd_card *card = platform_get_drvdata(pdev);
 
 	snd_card_free(card);
-	platform_set_drvdata(pdev, NULL);
 	return 0;
 }