Ensure generate nonce unavailable in decrypt

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index 0f74c54..e05c846 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -172,11 +172,12 @@
     unsigned int lengths_set : 1;
     unsigned int ad_started : 1;
     unsigned int body_started : 1;
+    unsigned int is_encrypt : 1;
 
     psa_driver_aead_context_t ctx;
 };
 
-#define PSA_AEAD_OPERATION_INIT {0, 0, 0, 0, 0, 0, 0, 0, 0, {0}}
+#define PSA_AEAD_OPERATION_INIT {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, {0}}
 static inline struct psa_aead_operation_s psa_aead_operation_init( void )
 {
     const struct psa_aead_operation_s v = PSA_AEAD_OPERATION_INIT;