dmaengine: fsl-edma: Fix return code for unhandled interrupts

For fsl,imx93-edma4 two DMA channels share the same interrupt.
So in case fsl_edma3_tx_handler is called for the "wrong"
channel, the return code must be IRQ_NONE. This signalize that
the interrupt wasn't handled.

Fixes: 72f5801 ("dmaengine: fsl-edma: integrate v3 support")
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Joy Zou <joy.zou@nxp.com>
Link: https://lore.kernel.org/r/20250424114829.9055-1-wahrenst@gmx.net
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/fsl-edma-main.c

@@ -57,7 +57,7 @@ static irqreturn_t fsl_edma3_tx_handler(int irq, void *dev_id)
 
 	intr = edma_readl_chreg(fsl_chan, ch_int);
 	if (!intr)
-		return IRQ_HANDLED;
+		return IRQ_NONE;
 
 	edma_writel_chreg(fsl_chan, 1, ch_int);