bom/Makefile: invoke eeschema to generate the BOM, some cleanup
bom/Makefile: invoke eeschema to generate the BOM, some cleanup

- Makefile: added %.lst target to generate the BOM with eeschema --bom
- Makefile: removed vpaths
- Makefile (spotless): remove .lst files as well
- Makefile (spotless): corrected typo arusb.ord (should be atusb.ord)

cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan