dmaengine: stm32-mdma: use dev_dbg on non-busy channel spurious it

If interrupt occurs while !chan->busy, it means channel has been disabled
between the raise of the interruption and the read of status and ien, so,
spurious interrupt can be silently discarded.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20220504155322.121431-4-amelie.delaunay@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: ADESTM

drivers/dma/stm32-mdma.c

@@ -1345,9 +1345,12 @@ static irqreturn_t stm32_mdma_irq_handler(int irq, void *devid)
 
 	if (!(status & ien)) {
 		spin_unlock(&chan->vchan.lock);
-		dev_warn(chan2dev(chan),
-			 "spurious it (status=0x%04x, ien=0x%04x)\n",
-			 status, ien);
+		if (chan->busy)
+			dev_warn(chan2dev(chan),
+				 "spurious it (status=0x%04x, ien=0x%04x)\n", status, ien);
+		else
+			dev_dbg(chan2dev(chan),
+				"spurious it (status=0x%04x, ien=0x%04x)\n", status, ien);
 		return IRQ_NONE;
 	}