Add preferences-desktop-tablet and preferences-desktop-touchpad icons
Summary:
KCM should use icons in preferences folder (always colorful) instead of devices folder (monochrome in small size)
Reviewers: Breeze, ngraham
Reviewed By: Breeze, ngraham
Subscribers: kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D29037