dma: mv_xor: add missing free_irq() call

Even though the driver cannot be unloaded at the moment, it is still
good to properly free the IRQ handlers in the channel removal function.

Signed-off-by: Thomas Petazzoni <[e-mail]>

drivers/dma/mv_xor.c

···
 		list_del(&chan->device_node);
 	}
 
+	free_irq(mv_chan->irq, mv_chan);
+
 	return 0;
 }
 
···
 	}
 
 	mv_chan->idx = idx;
+	mv_chan->irq = irq;
 
 	dma_dev = &mv_chan->dmadev;
 
···
 	/* clear errors before enabling interrupts */
 	mv_xor_device_clear_err_status(mv_chan);
 
-	ret = devm_request_irq(&pdev->dev, irq,
+	ret = devm_request_irq(&pdev->dev, mv_chan->irq,
 			       mv_xor_interrupt_handler,
 			       0, dev_name(&pdev->dev), mv_chan);
 	if (ret)

drivers/dma/mv_xor.h

···
 	spinlock_t		lock; /* protects the descriptor slot pool */
 	void __iomem		*mmr_base;
 	unsigned int		idx;
+	int                     irq;
 	enum dma_transaction_type	current_type;
 	struct list_head	chain;
 	struct list_head	completed_slots;