at91_ide: use readsw()/writesw() directly

Use readsw()/writesw() directly intead of __ide_mm_{in,out}sw() macros.

Cc: Stanislaw Gruszka <stf_xl@wp.pl>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>