IVGCVSW-2711 Add Serializer and Deserializer for Subtraction

Change-Id: I87836b5314c1f791b4df2ca90d239573ca28a2da
Signed-off-by: Conor Kennedy <conor.kennedy@arm.com>
Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
diff --git a/src/armnnSerializer/ArmnnSchema.fbs b/src/armnnSerializer/ArmnnSchema.fbs
index dea5889..9f1d8ec 100644
--- a/src/armnnSerializer/ArmnnSchema.fbs
+++ b/src/armnnSerializer/ArmnnSchema.fbs
@@ -106,7 +106,8 @@
     Floor = 22,
     BatchNormalization = 23,
     Greater = 24,
-    ResizeBilinear = 25
+    ResizeBilinear = 25,
+    Subtraction = 26
 }
 
 // Base layer table to be used as part of other layers
@@ -302,6 +303,10 @@
     dataLayout:DataLayout;
 }
 
+table SubtractionLayer {
+    base:LayerBase;
+}
+
 table BatchToSpaceNdLayer {
     base:LayerBase;
     descriptor:BatchToSpaceNdDescriptor;
@@ -402,7 +407,8 @@
     RsqrtLayer,
     FloorLayer,
     GreaterLayer,
-    ResizeBilinearLayer
+    ResizeBilinearLayer,
+    SubtractionLayer
 }
 
 table AnyLayer {