Tracing/QmlProfiler: Prepare for porting of shaders to Qt 6

This change touches up the shader handling code in Tracing and
QmlProfiler in order to pave the way for the pending porting of
the shaders to Qt 6.

- Use QSGGeometry::Attribute::createWithAttributeType instead of
  QSGGeometry::Attribute::create
- Undefine some fields that are unused in Qt 6
- Add a couple of comments to document the relation between C++
  variables and shader attributes
- Extract some code into functions

Change-Id: I0e7119484b6190a415a5c2d2a0bbd6465088cf19
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>

0 files changed, 0 insertions, 0 deletions