Make copy functions static-testable

This allows greater compiler optimisation.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/library/psa_crypto_invasive.h b/library/psa_crypto_invasive.h
index 58e357e..ec7183d 100644
--- a/library/psa_crypto_invasive.h
+++ b/library/psa_crypto_invasive.h
@@ -81,6 +81,13 @@
 psa_status_t psa_mac_key_can_do(
     psa_algorithm_t algorithm,
     psa_key_type_t key_type);
+
+psa_status_t psa_crypto_copy_input(const uint8_t *input, size_t input_len,
+                                   uint8_t *input_copy, size_t input_copy_len);
+
+psa_status_t psa_crypto_copy_output(const uint8_t *output_copy, size_t output_copy_len,
+                                    uint8_t *output, size_t output_len);
+
 #endif /* MBEDTLS_TEST_HOOKS && MBEDTLS_PSA_CRYPTO_C */
 
 #endif /* PSA_CRYPTO_INVASIVE_H */