debug/gdb: remove ncurses cleanup

That's legacy code that was usefull when ncurses was installed
in the sysroot. Still it's not longer the case (it's installed
in a special dedicated directory), we can remove that piece of
code.

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

 # m68k specific configuration file

 ## depends on EXPERIMENTAL

 ##

 ## select ARCH_SUPPORTS_32

 ## select ARCH_DEFAULT_32

 ## select ARCH_DEFAULT_BE

 ## select ARCH_SUPPORTS_WITH_CPU

 ##

 ## help The m68k architecture