ASoC: Intel: avs: Fix potential buffer overflow by snprintf()

snprintf() returns the would-be-filled size when the string overflows
the given buffer size, hence using this value may result in a buffer
overflow (although it's unrealistic).

This patch replaces it with a safer version, scnprintf() for papering
over such a potential issue.

Fixes: f1b3b320 ("ASoC: Intel: avs: Generic soc component driver")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220801165420.25978-2-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/avs/pcm.c

@@ -636,8 +636,8 @@ static ssize_t topology_name_read(struct file *file, char __user *user_buf, size
 	char buf[64];
 	size_t len;
 
-	len = snprintf(buf, sizeof(buf), "%s/%s\n", component->driver->topology_name_prefix,
-		       mach->tplg_filename);
+	len = scnprintf(buf, sizeof(buf), "%s/%s\n", component->driver->topology_name_prefix,
+			mach->tplg_filename);
 
 	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 }