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>

 # Linux kernel options

 config KERNEL_linux

     select KERNEL_SUPPORTS_SHARED_LIBS

     help

       Build a toolchain targeting systems running Linux as a kernel.