psa: Call export software implementation as a driver

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto_driver_wrappers.h b/library/psa_crypto_driver_wrappers.h
index fb32b8d..27d8b64 100644
--- a/library/psa_crypto_driver_wrappers.h
+++ b/library/psa_crypto_driver_wrappers.h
@@ -53,6 +53,11 @@
     uint8_t *key_buffer, size_t key_buffer_size,
     size_t *key_buffer_length, size_t *bits );
 
+psa_status_t psa_driver_wrapper_export_key(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    uint8_t *data, size_t data_size, size_t *data_length );
+
 psa_status_t psa_driver_wrapper_export_public_key(
     const psa_key_attributes_t *attributes,
     const uint8_t *key_buffer, size_t key_buffer_size,