fas216: return DID_ERROR for incomplete data transfer

fas216 returns DID_BAD_TARGET for an incomplete data
transfer. The midlayer uses DID_BAD_TARGET to signal
a non-existing or not reachable target. So we should
rather be using DID_ERROR here.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>