SE driver: Fix loading of persistent data

The persistent data was not loaded correctly (the code was loading 0
bytes instead of the correct size).
diff --git a/library/psa_crypto_se.c b/library/psa_crypto_se.c
index 11604c2..b7fa0c5 100644
--- a/library/psa_crypto_se.c
+++ b/library/psa_crypto_se.c
@@ -341,6 +341,8 @@
 
     driver_table[i].lifetime = lifetime;
     driver_table[i].methods = methods;
+    driver_table[i].internal.persistent_data_size =
+        methods->persistent_data_size;
 
     if( methods->persistent_data_size != 0 )
     {
@@ -358,8 +360,6 @@
         if( status != PSA_SUCCESS && status != PSA_ERROR_DOES_NOT_EXIST )
             goto error;
     }
-    driver_table[i].internal.persistent_data_size =
-        methods->persistent_data_size;
 
     return( PSA_SUCCESS );