ALSA: cmipci: Fix -Wformat-truncation warning

CMIPCI driver got compile warnings with -Wformat-truncation at a
couple of plain sprintf() usages.  Use scnprintf() for filling the
longname string for avoiding the warnings.

Link: https://lore.kernel.org/r/20230915082802.28684-13-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>