ALSA: usb-audio: qcom: Use snprintf for mixer control name formatting

ALSA: usb-audio: qcom: Use snprintf for mixer control name formatting

The current code uses sprintf() to format control names without bounds
checking, which could lead to buffer overflow if PCM index is large.
Replace sprintf with snprintf to ensure buffer safety.

The ctl_name buffer is 48 bytes, and the formatted string could exceed
this with large PCM index values. Using snprintf with sizeof(ctl_name)
prevents potential buffer overflow.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260603091102.231370-2-wangdich9700@163.com