ide: remove needless includes from ide-taskfile.c (take 2)

v2:

On Sunday 15 June 2008, Geert Uytterhoeven wrote:
> As ide-taskfile.c uses scatterlists, it should include <linux/scatterlist.h>.

(v1 broke IDE build on m68k, thanks to Geert for finding the bug)

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>