Prefer persistent over permanent

For consistency across the code base, prefer
persistent over permanent to qualify a key
stored in persistent storage.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 1f69b55..3e174f9 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1345,7 +1345,7 @@
         return( PSA_SUCCESS );
 
     /*
-     * Get the description of the key in a key slot. In case of a permanent
+     * Get the description of the key in a key slot. In case of a persistent
      * key, this will load the key description from persistent memory if not
      * done yet. We cannot avoid this loading as without it we don't know if
      * the key is operated by an SE or not and this information is needed by