dmaengine: at_xdmac: Remove unnecessary synchronize_irq() before free_irq()

Calling synchronize_irq() right before free_irq() is quite useless. On one
hand the IRQ can easily fire again before free_irq() is entered, on the
other hand free_irq() itself calls synchronize_irq() internally (in a race
condition free way), before any state associated with the IRQ is freed.

Patch was generated using the following semantic patch:
// <smpl>
@@
expression irq;
@@
-synchronize_irq(irq);
 free_irq(irq, ...);
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/at_xdmac.c

@@ -2007,8 +2007,6 @@ static int at_xdmac_remove(struct platform_device *pdev)
 	dma_async_device_unregister(&atxdmac->dma);
 	clk_disable_unprepare(atxdmac->clk);
 
-	synchronize_irq(atxdmac->irq);
-
 	free_irq(atxdmac->irq, atxdmac->dma.dev);
 
 	for (i = 0; i < atxdmac->dma.chancnt; i++) {