kconfig: print version in .config

Having the crosstool-NG version in the .config helps in case we
want to reproduce the toolchain with the exact same version of
crosstool-NG.

This also reverts #bb73e7632b54.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # m68k specific configuration file

 ## depends on EXPERIMENTAL

 ##

 ## select ARCH_SUPPORTS_32

 ## select ARCH_DEFAULT_32

 ## select ARCH_DEFAULT_BE

 ## select ARCH_SUPPORT_CPU

 ##

 ## help The m68k architecture