scripts: fix installing samples

It's been a while now that the working directory CT_WORK_DIR has
been changed from 'targets' to '.build'. Fix the install procedure
to properly tweak the installed samples.

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

 # m68k specific configuration file

 # depends on EXPERIMENTAL

 config ARCH_m68k

     select ARCH_SUPPORTS_32

     select ARCH_DEFAULT_32

     select ARCH_DEFAULT_BE

     select ARCH_SUPPORT_CPU

      help

       The m68k architecture