Fix ECIES clang-tidy dead-store and whitelist WOLFSSL_ECIES_STATIC_GCM_NONCE

.wolfssl_known_macro_extras

@@ -831,6 +831,7 @@ WOLFSSL_ECC_NO_SMALL_STACK
 WOLFSSL_ECC_SIGALG_PARAMS_NULL_ALLOWED
 WOLFSSL_ECDSA_MATCH_HASH
 WOLFSSL_ECDSA_SET_K_ONE_LOOP
+WOLFSSL_ECIES_STATIC_GCM_NONCE
 WOLFSSL_EC_POINT_CMP_JACOBIAN
 WOLFSSL_ED448_NO_LARGE_CODE
 WOLFSSL_EDDSA_CHECK_PRIV_ON_SIGN

wolfcrypt/src/ecc.c

@@ -15363,7 +15363,7 @@ int wc_ecc_encrypt_ex(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
                 ret = ecc_ctx_encrypt_advance(ctx);
             return ret;
         }
-        ret = 0; /* fall-through to software */
+        /* fall-through to software (ret is reassigned below) */
     }
 #endif
 
@@ -15860,7 +15860,7 @@ int wc_ecc_decrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
                 ret = ecc_ctx_decrypt_advance(ctx);
             return ret;
         }
-        ret = 0; /* fall-through to software */
+        /* fall-through to software (ret is reassigned below) */
     }
 #endif