Fix broken paths in kirigami.qrc.in

Summary: Fix path for private/CardsGridViewPrivate.qml and private/CardsListViewPrivate.qml.

Test Plan: Build fails due to missing files mentioned in summary. After applying the patch the paths are corrected.

Reviewers: Kirigami, VDG, apol

Reviewed By: apol

Subscribers: plasma-devel, VDG

Tags: Kirigami

Differential Revision: https://phabricator.kde.org/D28148