dmaengine: cirrus: check that output may be truncated

ep93xx_dma.c: In function 'ep93xx_dma_of_probe':
ep93xx_dma.c:1409:74: warning: '%u' directive output may be truncated
			       writing between 1 and 8 bytes into a region
			       of size 2 [-Wformat-truncation=]
		snprintf(dma_clk_name, sizeof(dma_clk_name), "m2p%u", i);
		                                                 ^~

Fixes: d7333f9d ("dmaengine: cirrus: use snprintf() to calm down gcc 13.3.0")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202409172024.pU8U5beA-lkp@intel.com/Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Link: https://lore.kernel.org/r/2bf9c37aad8f085839f9c63104f7275742f51945.camel@gmail.comSigned-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/dma/ep93xx_dma.c

@@ -1391,6 +1391,7 @@ static struct ep93xx_dma_engine *ep93xx_dma_of_probe(struct platform_device *pde
 	INIT_LIST_HEAD(&dma_dev->channels);
 	for (i = 0; i < edma->num_channels; i++) {
 		struct ep93xx_dma_chan *edmac = &edma->channels[i];
+		int len;
 
 		edmac->chan.device = dma_dev;
 		edmac->regs = devm_platform_ioremap_resource(pdev, i);
@@ -1404,9 +1405,11 @@ static struct ep93xx_dma_engine *ep93xx_dma_of_probe(struct platform_device *pde
 		edmac->edma = edma;
 
 		if (edma->m2m)
-			snprintf(dma_clk_name, sizeof(dma_clk_name), "m2m%u", i);
+			len = snprintf(dma_clk_name, sizeof(dma_clk_name), "m2m%u", i);
 		else
-			snprintf(dma_clk_name, sizeof(dma_clk_name), "m2p%u", i);
+			len = snprintf(dma_clk_name, sizeof(dma_clk_name), "m2p%u", i);
+		if (len >= sizeof(dma_clk_name))
+			return ERR_PTR(-ENOBUFS);
 
 		edmac->clk = devm_clk_get(dev, dma_clk_name);
 		if (IS_ERR(edmac->clk)) {