Remove accidentally slipped back traces of cmake code for Plasma style
Summary:
Removed in e914e6323277f7963334897410bd9b7f8341f2ed,
accidentally added back in 8c34dde112e7166dd0ba116022a70586a7c5ade6
Reviewers: mart
Reviewed By: mart
Subscribers: plasma-devel
Tags: Kirigami
Differential Revision: https://phabricator.kde.org/D21784