Make {USE_,}PSA_{INIT,DONE} available in all test suites

Make USE_PSA_INIT() and USE_PSA_DONE() available in all test suites in
all cases, doing nothing if MBEDTLS_USE_PSA_CRYPTO is disabled. Use
those in preference to having explicit
defined(MBEDTLS_USE_PSA_CRYPTO) checks (but there may still be places
left where using the new macros would be better).

Also provide PSA_INIT() by symmetry with PSA_DONE(), functional
whenver MBEDTLS_PSA_CRYPTO_C is enabled, but currently unused.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 5c97d90..93cf50c 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -3836,9 +3836,7 @@
     if( output == NULL )
         goto exit;
 
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
-    TEST_ASSERT( psa_crypto_init() == 0 );
-#endif
+    USE_PSA_INIT( );
 
     TEST_ASSERT( mbedtls_ssl_tls_prf( type, secret->x, secret->len,
                                       label, random->x, random->len,