tttocea608: only warn when we do drop characters
tttocea608: only warn when we do drop characters

In roll-up mode, we drop out of the loop and warn when the 32nd
character is reached, the warning is unnecessary when there were
no characters left to loop on.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/499>

sdroege/rsplugin,sdroege/rsplugin