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 *

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>