Introduce project_crypto_name in build_tree.py

Add new function to build_tree.py to return the crypto
name for the project; either tfpsacrypto or mbedcrypto.
Deploy this function where needed.

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 2482d03..82cc1b1 100755
--- a/tests/scripts/test_psa_compliance.py
+++ b/tests/scripts/test_psa_compliance.py
@@ -50,10 +50,7 @@
 
     in_tf_psa_crypto_repo = build_tree.looks_like_tf_psa_crypto_root(root_dir)
 
-    if in_tf_psa_crypto_repo:
-        crypto_name = 'tfpsacrypto'
-    else:
-        crypto_name = 'mbedcrypto'
+    crypto_name = build_tree.project_crypto_name()
 
     library_subdir = build_tree.crypto_core_directory()