generator.yml has become quite long as our matrix has grown, currently
coming in at 4458 lines. It is easy to get lost when modifying multiple
different trees and LLVM versions.
Decompose generator.yml into individual YAML files for each section. We
can dynamically rebuild generator.yml from all of these pieces in
utils.get_config_from_generator() and pass that along to yaml.load().
There is currently no functional change. In the future, this will make
it easier to add new LLVM versions, as we can copy and modify whole
files rather than specific ranges in generator.yml.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>