added an useless message

v4l2/grabvidseq.c

@@ -80,6 +80,9 @@ puts("\t-s WxH\t\tsize of capture");
 puts("\t-c mode\t\tcontrast enhancement");
 puts("\t-u\t\ttry upscaling...");
 puts("\t-v\t\tincrease verbosity");
+if (verbosity) {
+	puts("\n\t\tXXX list all the contrast modes, please\n");
+	}
 exit(0);
 }
 /* --------------------------------------------------------------------- */