ALSA: ISA: Remove superfluous *_set_drvdata(NULL) calls

Similarly like the previous commit for PCI drivers, remove
dev_set_drvdata(NULL) and pnp_set_drvdata(NULL) calls in ISA drivers
now.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/msnd/msnd_pinnacle.c

@@ -1064,7 +1064,6 @@ cfg_error:
 static int snd_msnd_isa_remove(struct device *pdev, unsigned int dev)
 {
 	snd_msnd_unload(dev_get_drvdata(pdev));
-	dev_set_drvdata(pdev, NULL);
 	return 0;
 }