[SCSI] NCR5380: Fix bugs and canonicalize irq handler usage

* Always pass the same value to free_irq() that we pass to
  request_irq().  This fixes several bugs.

* Always call NCR5380_intr() with 'irq' and 'dev_id' arguments.

  Note, scsi_falcon_intr() is the only case now where dev_id is not the
  scsi_host.

* Always pass Scsi_Host to request_irq().  For most cases, the drivers
  already did so, and I merely neated the source code line.  In other
  cases, either NULL or a non-sensical value was passed, verified to be
  unused, then changed to be Scsi_Host in anticipation of the future.

In addition to the bugs fixes, this change makes the interface usage
consistent, which in turn enables the possibility of directly
referencing Scsi_Host from all NCR5380_intr() invocations.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/mac_scsi.c b/drivers/scsi/mac_scsi.c
index abe2bda..3b09ab2 100644
--- a/drivers/scsi/mac_scsi.c
+++ b/drivers/scsi/mac_scsi.c
@@ -303,7 +303,7 @@
 
     if (instance->irq != SCSI_IRQ_NONE)
 	if (request_irq(instance->irq, NCR5380_intr, IRQ_FLG_SLOW, 
-		"ncr5380", instance)) {
+			"ncr5380", instance)) {
 	    printk(KERN_WARNING "scsi%d: IRQ%d not free, interrupts disabled\n",
 		   instance->host_no, instance->irq);
 	    instance->irq = SCSI_IRQ_NONE;
@@ -326,7 +326,7 @@
 int macscsi_release (struct Scsi_Host *shpnt)
 {
 	if (shpnt->irq != SCSI_IRQ_NONE)
-		free_irq (shpnt->irq, NCR5380_intr);
+		free_irq(shpnt->irq, shpnt);
 	NCR5380_exit(shpnt);
 
 	return 0;