IconItem: remove remaining & unused smooth property bits
Summary: fix-up for 18a2ca50ab092e27a3464fca8d515cb7791c7d5a
Reviewers: Plasma, davidedmundson, apol
Reviewed By: apol
Subscribers: kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D20999