Move AEAD contexts from primitives to composites

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/include/psa/crypto_driver_contexts_composites.h b/include/psa/crypto_driver_contexts_composites.h
index 239fdcb..957986c2 100644
--- a/include/psa/crypto_driver_contexts_composites.h
+++ b/include/psa/crypto_driver_contexts_composites.h
@@ -58,5 +58,13 @@
 #endif
 } psa_driver_mac_context_t;
 
+typedef union {
+    unsigned dummy; /* Make sure this union is always non-empty */
+    mbedtls_psa_aead_operation_t mbedtls_ctx;
+#if defined(PSA_CRYPTO_DRIVER_TEST)
+    mbedtls_transparent_test_driver_aead_operation_t transparent_test_driver_ctx;
+#endif
+} psa_driver_aead_context_t;
+
 #endif /* PSA_CRYPTO_DRIVER_CONTEXTS_COMPOSITES_H */
 /* End of automatically generated file. */