Update old class names

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/tests/scripts/depends.py b/tests/scripts/depends.py
index 1990cd2..64a3d46 100755
--- a/tests/scripts/depends.py
+++ b/tests/scripts/depends.py
@@ -537,7 +537,7 @@
                             default=True)
         options = parser.parse_args()
         os.chdir(options.directory)
-        conf = config.ConfigFile(options.config)
+        conf = config.MbedTLSConfig(options.config)
         domain_data = DomainData(options, conf)
 
         if options.tasks is True: