[coreboot] Makefile indentation for conditionals

[Maximilian Brune]

Hi

Reading Makefiles especially in big projects like coreboot is a constant.
pain. One of the big issues is that conditionals are very hard to read
since we cannot use tabs for indentation. Has anyone ever thought about
using whitespaces as indentation for conditionals in our Makefiles or is
that connected to known problems?

greetings
Max