qt5webengine: fix chromium-latest.inc with the current license files

chromium-latest.inc was not properly updated with the latest version
bumps of Qt, and it no longer matches the license files of
Qt5Webengine 5.11. This commit fixes this legal-info failure:

$ make qt5webengine-legal-info
[...]
cp: cannot stat '/home/thomas/projets/buildroot/output/build/qt5webengine-5.11.1/src/3rdparty/chromium/buildtools/third_party/libc++abi/trunk/LICENSE.TXT': No such file or directory

Signed-off-by: Laurent Hartanerot <laurent.hartanerot@atos.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>