[SCSI] arcmsr: irq handler fixes, cleanups, micro-opts

* Remove IRQF_DISABLED, it is clearly wrong for this driver.

* Remove wasteful spin_lock_irqsave() in interrupt handler.
  The lighter-weight spin_lock() is all that's needed.

* Annotate with FIXME where arcmsr_interrupt() is called
  without any spinlock being acquired.

* Eliminate pointless cast from void pointer in arcmsr_do_interrupt()

[jejb: conflict resolution]
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Acked-by: Nick Cheng <nick.cheng@areca.com.tw>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/arcmsr/arcmsr_hba.c

@@ -422,7 +422,7 @@ static int arcmsr_probe(struct pci_dev *pdev,
 		goto out_release_regions;
 
 	error = request_irq(pdev->irq, arcmsr_do_interrupt,
-				IRQF_SHARED, "arcmsr", acb);
+			    IRQF_SHARED, "arcmsr", acb);
 	if (error)
 		goto out_free_ccb_pool;