[coreboot] v3 makefile bugs

[Carl-Daniel Hailfinger]

Hi,

I just tried make randconfig to test whether all allowed configuations 
can be built. The result was disastrous.
Without a make distclean before make randconfig, I get all sorts of 
compile errors for about 60% of the randomly generated .config files.
With make distclean before make randconfig, most of the configurations 
built successfully.

This means that some dependencies are wrong, resulting in incorrect builds.

To reproduce, simply run "make randconfig; make;" in a loop. It will 
fail after two or three iterations.

Regards,
Carl-Daniel