Fix incorrect paths to generate_psa_constants.py

This commit fixes incorrect paths to generate_psa_constants.py after
being moves to tf-psa-crypto.

Signed-off-by: Harry Ramsey <harry.ramsey@arm.com>

tf-psa-crypto/scripts/framework_scripts_path.py

@@ -13,5 +13,6 @@ import os
 import sys
 
 sys.path.append(os.path.join(os.path.dirname(__file__),
+                             os.path.pardir,
                              os.path.pardir,
                              'framework', 'scripts'))