TPAC: Don't display serial headers without content

Currently, the TPAC serial display code will print a section
header, then see if there is any content to show.  This causes
headers to show up when they are unnecessary or unwanted.

Now, we only show the header if we have content needing heading.

Signed-off-by: Dan Wells <dbw2@calvin.edu>
Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>