Add attributes to serialization of custom op

Change-Id: I4a1d7675b247efcf34aadd59eac17b966e3705af
Signed-off-by: Eric Kunze <eric.kunze@arm.com>
diff --git a/schema/tosa.fbs b/schema/tosa.fbs
index 4d5c611..093c235 100644
--- a/schema/tosa.fbs
+++ b/schema/tosa.fbs
@@ -1,5 +1,5 @@
 
-// Copyright (c) 2020-2021, ARM Limited.
+// Copyright (c) 2020-2023, ARM Limited.
 //
 //    Licensed under the Apache License, Version 2.0 (the "License");
 //    you may not use this file except in compliance with the License.
@@ -161,7 +161,8 @@
   TableAttribute,
   MatMulAttribute,
   FullyConnectedAttribute,
-  NegateAttribute
+  NegateAttribute,
+  CustomAttribute
 }
 
 table PoolAttribute {
@@ -281,6 +282,12 @@
   output_zp: int32;
 }
 
+table CustomAttribute {
+  identifier:string;
+  config:string;
+  implementation_attrs:[ubyte];
+}
+
 table Version {
   _major: int32 = 0;
   _minor: int32 = 51;