Initialize PSA crypto in test_suite_x509write for RSA signing tests

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index 261794c..1e88191 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -93,6 +93,8 @@
 
     memset( &rnd_info, 0x2a, sizeof( mbedtls_test_rnd_pseudo_info ) );
 
+    USE_PSA_INIT( );
+
     mbedtls_pk_init( &key );
     TEST_ASSERT( mbedtls_pk_parse_keyfile( &key, key_file, NULL,
                         mbedtls_test_rnd_std_rand, NULL ) == 0 );
@@ -140,6 +142,7 @@
 exit:
     mbedtls_x509write_csr_free( &req );
     mbedtls_pk_free( &key );
+    USE_PSA_DONE( );
 }
 /* END_CASE */
 
@@ -220,6 +223,8 @@
     memset( &rnd_info, 0x2a, sizeof( mbedtls_test_rnd_pseudo_info ) );
     mbedtls_mpi_init( &serial );
 
+    USE_PSA_INIT( );
+
     mbedtls_pk_init( &subject_key );
     mbedtls_pk_init( &issuer_key  );
     mbedtls_pk_init( &issuer_key_alt );
@@ -316,6 +321,7 @@
     mbedtls_pk_free( &subject_key );
     mbedtls_pk_free( &issuer_key );
     mbedtls_mpi_free( &serial );
+    USE_PSA_DONE( );
 }
 /* END_CASE */