scripts: simplify and fix the toolchain config script

The script that is installed, and which sole purpose is to dump
the .config that was used to build the toolchain, is pure insanity.

Let's make it much, much more simpler...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from 814ea73df7e0fab3db1cbe7623932714359c732b)

 # Alpha specific configuration file

 ## select ARCH_SUPPORTS_32

 ## select ARCH_DEFAULT_32

 ## select ARCH_USE_MMU

 ## select ARCH_SUPPORT_CPU

 ## select ARCH_SUPPORT_TUNE

 ##

 ## help The Alpha architecture.