candump: silence format-overflow warning

When -Wformat-overflow= is enabled the gcc notes ...
"‘sprintf’ output between 30 and 82 bytes into a destination of size xx"
Increasing the buffer for the file name to 83 bytes removes the warning.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>

candump.c

@@ -620,7 +620,7 @@ int main(int argc, char **argv)
 	if (log) {
 		time_t currtime;
 		struct tm now;
-		char fname[sizeof("candump-2006-11-20_202026.log")+1];
+		char fname[83]; /* suggested by -Wformat-overflow= */
 
 		if (time(&currtime) == (time_t)-1) {
 			perror("time");