audio: Use GCC_FMT_ATTR (format checking)

Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

audio/audio_pt_int.c

@@ -8,7 +8,8 @@
 
 #include <signal.h>
 
-static void logerr (struct audio_pt *pt, int err, const char *fmt, ...)
+static void GCC_FMT_ATTR(3, 4) logerr (struct audio_pt *pt, int err,
+                                       const char *fmt, ...)
 {
     va_list ap;