powerpc/powermac: Use generic_handle_irq() in gatwick_action()

Don't call __do_IRQ() directly in gatwick_action(), use
generic_handle_irq().
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powermac/pic.c

@@ -221,7 +221,7 @@ static irqreturn_t gatwick_action(int cpl, void *dev_id)
 			continue;
 		irq += __ilog2(bits);
 		spin_unlock_irqrestore(&pmac_pic_lock, flags);
-		__do_IRQ(irq);
+		generic_handle_irq(irq);
 		spin_lock_irqsave(&pmac_pic_lock, flags);
 		rc = IRQ_HANDLED;
 	}