Initialize & free PSA in test_multiple_psks()

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index e42f8ba..35f1638 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -5310,6 +5310,7 @@
 
     mbedtls_ssl_config conf;
 
+    USE_PSA_INIT( );
     mbedtls_ssl_config_init( &conf );
 
     TEST_ASSERT( mbedtls_ssl_conf_psk( &conf,
@@ -5323,6 +5324,8 @@
 exit:
 
     mbedtls_ssl_config_free( &conf );
+
+    USE_PSA_DONE( );
 }
 /* END_CASE */