patman: Don't clear progress in tout unless it was used

At present calling Uninit() always called ClearProgress() which outputs
a \r character as well as spaces to remove any progress information on the
line. This can mess up the normal output of binman and other tools. Fix
this by outputing this only when progress information has actually been
previous written.

Signed-off-by: Simon Glass <sjg@chromium.org>