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

In the Linux kernel, the following vulnerability has been resolved: 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.