cmake: flash: Remove fake path to zephyr_flash_debug.py

We append a path to the FLASH_SCRIPT/DEBUG_SCRIPT that was bogus and not
really needed by zephyr_flash_debug.py.  So lets remove it since its
just confusing.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
diff --git a/cmake/flash/CMakeLists.txt b/cmake/flash/CMakeLists.txt
index b3ddde7..d28b750 100644
--- a/cmake/flash/CMakeLists.txt
+++ b/cmake/flash/CMakeLists.txt
@@ -42,7 +42,7 @@
       ${PYTHON_EXECUTABLE}
       $ENV{ZEPHYR_BASE}/scripts/support/zephyr_flash_debug.py
       ${target}
-      $ENV{ZEPHYR_BASE}/scripts/support/${script}
+      ${script}
       DEPENDS ${logical_target_for_zephyr_elf}
       WORKING_DIRECTORY ${APPLICATION_BINARY_DIR}
       )