GitLab

Update all available SRCREVs and remove obsolete patches

https://code.qt.io/cgit/qt/qtreleasenotes.git/about/qt/5.15.8/release-note.md
https://code.qt.io/cgit/qt/qtreleasenotes.git/about/qt/5.15.9/release-note.md

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>