fix(cublas): copy include dirs containing files without .h extension

nv/target has no .h suffix; use -type f instead of -name '*.h' to
detect non-empty include directories.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/builder/build-cublas.sh

@@ -126,7 +126,7 @@ copy_headers() {
         case "$inc_dir" in
             */usr/include) ;;  # already handled above
             *)
-                if find "${inc_dir}" -name '*.h' -maxdepth 2 | grep -q .; then
+                if find "${inc_dir}" -maxdepth 3 \( -name '*.h' -o -type f \) | grep -q .; then
                     cp -a "${inc_dir}/." "${CACHE_DIR}/include/"
                 fi
                 ;;