dmaengine :ipu: change ipu_irq_handler() to remove compile warning

Change ipu_irq_handler() to avoid gcc warning:

drivers/dma/ipu/ipu_irq.c:305:4: warning: 'irq' may be used
uninitialized in this function [-Wmaybe-uninitialized]
    generic_handle_irq(irq);
Signed-off-by: yalin wang <yalin.wang2010@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/ipu/ipu_irq.c

@@ -286,7 +286,7 @@ static void ipu_irq_handler(unsigned int __irq, struct irq_desc *desc)
 		raw_spin_unlock(&bank_lock);
 		while ((line = ffs(status))) {
 			struct ipu_irq_map *map;
-			unsigned int irq;
+			unsigned int irq = NO_IRQ;
 
 			line--;
 			status &= ~(1UL << line);