[nxp noup][examples][k32w0] Fix sign script location path

The path should be relative to the current file to take into
account different build scripts that might change the location
of the gn target, which will affect the relative location of
the sign script.

Signed-off-by: marius-alex-tache <marius.tache@nxp.com>

Author: marius-alex-tache

examples/platform/nxp/k32w/k32w0/scripts/sign-outdir.py

@@ -11,7 +11,8 @@ def main(args):
             path_prefix = "/core"
         sign_images_path = os.environ["NXP_K32W0_SDK_ROOT"] + path_prefix + "/tools/imagetool/sign_images.sh"
     else:
-        sign_images_path = os.getcwd() + "/../../../../../../../third_party/nxp/github_sdk/k32w0/repo/core/tools/imagetool/sign_images.sh"
+        sign_images_path = os.path.abspath(
+            __file__ + "/../../../../../../../third_party/nxp/github_sdk/k32w0/repo/core/tools/imagetool/sign_images.sh")
 
     # Give execute permission if needed
     if os.access(sign_images_path, os.X_OK) is False: