staging: comedi: rtf520: las0, las1, and lcfg are void __iomem *

The las0, las1, and lcfg variables in struct rtdPrivate are all ioremap'ed pci resources and should be void __iomem * not void *.

This quiets a lot of sparse warings for the writel and readl like:

warning: incorrect type in argument 1 (different address spaces) expected void const volatile [noderef] <asn:2>*addr got void *<noident>

warning: incorrect type in argument 2 (different address spaces) expected void volatile [noderef] <asn:2>*addr
   got void *

---

index 0c15b82..0e62bae 100644
@@ -339,9 +339,9 @@ static const struct rtdBoard rtd520Boards[] = {
 */
 struct rtdPrivate {
 	/* memory mapped board structures */
-	void *las0;
-	void *las1;
-	void *lcfg;
+	void __iomem *las0;
+	void __iomem *las1;
+	void __iomem *lcfg;
 
 	unsigned long intCount;	/* interrupt count */
 	long aiCount;		/* total transfer size (samples) */