Update help

git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@1260 0c269be4-1314-0410-8aa9-9f06e86f4224

common/Jackdmp.cpp

@@ -84,7 +84,7 @@ static void usage (FILE* file)
              "               [ --sync OR -S ]\n"
              "               [ --version OR -V ]\n"
              "         -d driver [ ... driver args ... ]\n"
-             "             where driver can be `alsa', `coreaudio' or `dummy'\n"
+             "             where driver can be `alsa', `coreaudio', 'portaudio' or `dummy'\n"
              "       jackdmp -d driver --help\n"
              "             to display options for each driver\n\n");
 }