Remove virtual for non-virtual calls
Summary:
TerminalDisplay is internal to Konsole, and it's never inherited,
that means that the 'virtual' on those functions are dummy and
does nothing besides increase the VTable size.
Reviewers: Konsole, hindenburg
Reviewed By: Konsole, hindenburg
Subscribers: konsole-devel
Tags: Konsole
Differential Revision: https://phabricator.kde.org/D17222