Swarm: Fix crash due to missing initialization

If things are just right this will result in the hws[0]->parent being
passed to ide_host_add() being non-zero and an ooops a little later.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>