psa: Call export software implementation as a driver

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/include/test/drivers/key_management.h b/tests/include/test/drivers/key_management.h
index 7811fb4..9d51758 100644
--- a/tests/include/test/drivers/key_management.h
+++ b/tests/include/test/drivers/key_management.h
@@ -58,6 +58,11 @@
     const psa_key_attributes_t *attributes,
     uint8_t *key, size_t key_size, size_t *key_length );
 
+psa_status_t test_opaque_export_key(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key, size_t key_length,
+    uint8_t *data, size_t data_size, size_t *data_length );
+
 psa_status_t test_transparent_export_public_key(
     const psa_key_attributes_t *attributes,
     const uint8_t *key, size_t key_length,