macio: use the existing IDEDMA aiocb to hold the active DMA aiocb

macio: use the existing IDEDMA aiocb to hold the active DMA aiocb

Currently the aiocb is held within MACIOIDEState, however the IDE core code
assumes that the current actvie DMA aiocb is held in aiocb in a few places,
e.g. ide_bus_reset() and ide_reset().

Switch over to using IDEDMA aiocb to store the aiocb for the current active
DMA request so that bus resets and restarts are handled correctly. As a
consequence we can now use ide_set_inactive() rather than handling its
functionality ourselves.

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