Revert change that removed in_tf_psa_crypto_repo variable

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/tests/scripts/test_psa_compliance.py b/tests/scripts/test_psa_compliance.py
index e2ccea3..034949b 100755
--- a/tests/scripts/test_psa_compliance.py
+++ b/tests/scripts/test_psa_compliance.py
@@ -48,6 +48,8 @@
 def main(library_build_dir: str):
     root_dir = os.getcwd()
 
+    in_tf_psa_crypto_repo = build_tree.looks_like_tf_psa_crypto_root(root_dir)
+
     crypto_name = build_tree.project_crypto_name(root_dir)
     library_subdir = build_tree.crypto_core_directory(root_dir)