powerpc/pseries: Use irq_has_action() in eeh_disable_irq()

Rather than open-coding our own check, use irq_has_action()
to check if an irq has an action - ie. is "in use".

irq_has_action() doesn't take the descriptor lock, but it
shouldn't matter - we're just using it as an indicator
that the irq is in use. disable_irq_nosync() will take
the descriptor lock before doing anything also.

Signed-off-by: Michael Ellerman <[e-mail]>
Acked-by: Grant Likely <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/platforms/pseries/eeh_driver.c

···
 }
 #endif
 
-/** 
- * irq_in_use - return true if this irq is being used 
- */
-static int irq_in_use(unsigned int irq)
-{
-	int rc = 0;
-	unsigned long flags;
-   struct irq_desc *desc = irq_desc + irq;
-
-	spin_lock_irqsave(&desc->lock, flags);
-	if (desc->action)
-		rc = 1;
-	spin_unlock_irqrestore(&desc->lock, flags);
-	return rc;
-}
-
 /**
  * eeh_disable_irq - disable interrupt for the recovering device
  */
···
 	if (dev->msi_enabled || dev->msix_enabled)
 		return;
 
-	if (!irq_in_use(dev->irq))
+	if (!irq_has_action(dev->irq))
 		return;
 
 	PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;