scsi: aic94xx: fix calls to dma_set_mask_and_coherent()

The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded.

[mkp: fixed subject]

Fixes: 3a21986f

 ("scsi: aic94xx: fully convert to the generic DMA API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>