Create data/ dir, move cli, 9p and readfile there.

build

@@ -159,11 +159,10 @@ BR2_ROOTFS_POST_SCRIPT_ARGS=\"$post_script_args\"
   make O="$buildroot_out_dir" olddefconfig
 fi
 
-# Build.
 mkdir -p \
   "${gem5_out_dir}" \
   "${qemu_out_dir}" \
-  "${root_dir}/9p" \
+  "${p9_dir}" \
 ;
 cd "${buildroot_dir}"
 # HOST_QEMU_OPTS is a hack that happens to work because the QEMU package luckly uses += at all times.