Revert "dc395x: Fix support for highmem"

It introduces a repeatable oops in the driver, which is a bigger problem
than the patch tries to solve. From the original description:

    Author: Jamie Lenehan <lenehan@twibble.org>
    Date:   Thu Mar 3 14:41:40 2005 +0200

    [PATCH] dc395x: Fix support for highmem

    From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>

    Removes the page_to_virt and maps sg lists dynamically.
    This makes the driver work with highmem pages.

    Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
    Signed-off-by: Jamie Lenehan <lenehan@twibble.org>
    Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>