aha1542: Change aha1542_set_bus_times parameters

Pass struct Scsi_Host *sh and dma parameters instead of index to
aha1542_set_bus_times.
This is required for printk conversion.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>