dmaengine: cirrus: use snprintf() to calm down gcc 13.3.0

Even though it's a false positive (highest channel number is "9"), refer to
"struct ep93xx_edma_data edma_m2p", we can avoid new warning by using
snprintf().

drivers/dma/ep93xx_dma.c: In function 'ep93xx_dma_of_probe':
>> drivers/dma/ep93xx_dma.c:1365:51: warning: '%u' directive writing between 1 and 8 bytes into a region of size 2 [-Wformat-overflow=]
1365 | sprintf(dma_clk_name, "m2p%u", i);
| ^~
drivers/dma/ep93xx_dma.c:1365:47: note: directive argument in the range [0, 16777216]
1365 | sprintf(dma_clk_name, "m2p%u", i);
| ^~~~~~~
drivers/dma/ep93xx_dma.c:1365:25: note: 'sprintf' output between 5 and 12 bytes into a destination of size 5
1365 | sprintf(dma_clk_name, "m2p%u", i);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 4e8ad5ed845b ("dmaengine: cirrus: Convert to DT for Cirrus EP93xx")
Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Signed-off-by: Alexander Sverdlin <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

drivers/dma/ep93xx_dma.c

···
 		edmac->edma = edma;
 
 		if (edma->m2m)
-			sprintf(dma_clk_name, "m2m%u", i);
+			snprintf(dma_clk_name, sizeof(dma_clk_name), "m2m%u", i);
 		else
-			sprintf(dma_clk_name, "m2p%u", i);
+			snprintf(dma_clk_name, sizeof(dma_clk_name), "m2p%u", i);
 
 		edmac->clk = devm_clk_get(dev, dma_clk_name);
 		if (IS_ERR(edmac->clk)) {