firmware-utils: when using open with O_CREAT and O_WRONLY, also use O_TRUNC to ensure that overwritten files have the right size (fixes #3505)

SVN-Revision: 12667

tools/firmware-utils/src/ptgen.c

@@ -143,7 +143,7 @@ static int gen_ptable(int nr)
 		printf("%ld\n", ((long) len * 512));
 	}
 
-	if ((fd = open(filename, O_WRONLY|O_CREAT, 0644)) < 0) {
+	if ((fd = open(filename, O_WRONLY|O_CREAT|O_TRUNC, 0644)) < 0) {
 		fprintf(stderr, "Can't open output file '%s'\n",filename);
 		return -1;
 	}