Add new signedness attributes to RESCALE

Signed-off-by: Eric Kunze <eric.kunze@arm.com>
Change-Id: I96202b90bff833654735a2f2306eb782d202b6e6
diff --git a/schema/tosa.fbs b/schema/tosa.fbs
index 9033351..c2f834f 100644
--- a/schema/tosa.fbs
+++ b/schema/tosa.fbs
@@ -216,6 +216,8 @@
   scale32: bool;
   double_round: bool;
   per_channel: bool;
+  input_unsigned: bool;
+  output_unsigned: bool;
 }
 
 table MulAttribute {