ALSA: sh_dac_audio: 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 <sachin.kamat@linaro.org>
Cc: Rafael Ignacio Zurita <rizurita@yahoo.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/sh/sh_dac_audio.c

@@ -290,8 +290,6 @@ static int snd_sh_dac_pcm(struct snd_sh_dac *chip, int device)
 static int snd_sh_dac_remove(struct platform_device *devptr)
 {
 	snd_card_free(platform_get_drvdata(devptr));
-	platform_set_drvdata(devptr, NULL);
-
 	return 0;
 }