SWARM IDE: Fix up following changes to ide_hwif_t

 Following recent changes to ide_hwif_t update the SWARM IDE driver to use 
hw_regs_t to initialize port mapping.  Plus minor layout adjustments along 
the lines of other drivers.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>