(trivial) treewide: mark pGC->ops->CopyArea() calls not using result as void
We alread have several of these calls, that aren't interested in result value, explicitly casting to void. Fixing this up for the remaining ones.
This is helpful for the human reader as well as quality analysis tools.
Signed-off-by: Enrico Weigelt, metux IT consult info@metux.net