lirc: fix build against pyyaml-6.0
Without the change `lirc` build fails as:
```
$ nix build -f. -L lirc
...
PYTHONPATH=../python-pkg/lirc \
/nix/store/gn4gyzv93izh3lg5iqjb7l04k9r4hxv0-python3-3.9.9-env/bin/python ./data2hwdb ../configs ../configs \
> lirc.hwdb
Traceback (most recent call last):
File "/build/lirc-0.10.1/doc/./data2hwdb", line 112, in <module>
main()
File "/build/lirc-0.10.1/doc/./data2hwdb", line 100, in main
db = database.Database(configdir, yamldir)
File "/build/lirc-0.10.1/python-pkg/lirc/database.py", line 135, in __init__
cf = yaml.load(f.read())
TypeError: load() missing 1 required positional argument: 'Loader'
make[2]: *** [Makefile:1263: lirc.hwdb] Error 1
```
b5fbd8a057