scsi: aha1542: Fix zeroday __udivdi3 warning

dma_addr_t can be u64 on pae systems but isa_virt_to_bus only ever
returns unsigned long (because an ISA physical address can only be 24
bits). Cast to unsigned long to avoid division.

Fixes: 1794ef2b ("scsi: aha1542: convert to DMA mapping API")
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aha1542.c

@@ -325,7 +325,7 @@ static irqreturn_t aha1542_interrupt(int irq, void *dev_id)
 			return IRQ_HANDLED;
 		};
 
-		mbo = (scsi2int(mb[mbi].ccbptr) - aha1542->ccb_handle) / sizeof(struct ccb);
+		mbo = (scsi2int(mb[mbi].ccbptr) - (unsigned long)aha1542->ccb_handle) / sizeof(struct ccb);
 		mbistatus = mb[mbi].status;
 		mb[mbi].status = 0;
 		aha1542->aha1542_last_mbi_used = mbi;