pata_ixp4xx_cf: fix oops on detach

pata_ixp4xx_cf dodged dont-clear-drvdata-in-LLD bombing run as it used
platform_set_drvdata() instead of dev_set_drvdata().  This causes OOPS
on devres host release.  Kill it.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/pata_ixp4xx_cf.c

@@ -232,7 +232,6 @@ static __devexit int ixp4xx_pata_remove(struct platform_device *dev)
 	struct ata_host *host = platform_get_drvdata(dev);
 
 	ata_host_detach(host);
-	platform_set_drvdata(dev, NULL);
 
 	return 0;
 }