One of the reasons macio_ide_register_dma() needs to exist is because the
channel id isn't passed into the MACIO_IDE object. Pass in the channel id
using a qdev property to remove this requirement.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>