config.py: Do not set default entry for tf-psa-crypto config.

Both type of config entries, boolean and value containing
reside in tf-psa-crypto confing files.

A default value will now be set only for PSA_WANT_X symbols.

Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>

scripts/config.py

@@ -420,7 +420,7 @@ class CombinedConfig(config_common.Config):
                 raise ValueError(f'Feature is unstable: \'{name}\'')
 
             # The default value in the crypto config is '1'
-            if not value:
+            if not value and re.match(self._crypto_regexp, name):
                 value = '1'
 
         if name not in self.settings: