IVGCVSW-3269 Add Serialization support for the new Prelu Activation layer

 * Adds serialization/deserialization support
 * Adds related unit test

Signed-off-by: Ellen Norris-Thompson <ellen.norris-thompson@arm.com>
Change-Id: I600322b03e51f443cbcd9262bb27e36e5fd95ae5
diff --git a/src/armnnSerializer/ArmnnSchema.fbs b/src/armnnSerializer/ArmnnSchema.fbs
index 1204ad8..db5672f 100644
--- a/src/armnnSerializer/ArmnnSchema.fbs
+++ b/src/armnnSerializer/ArmnnSchema.fbs
@@ -122,7 +122,8 @@
     Merge = 37,
     Switch = 38,
     Concat = 39,
-    SpaceToDepth = 40
+    SpaceToDepth = 40,
+    Prelu = 41
 }
 
 // Base layer table to be used as part of other layers
@@ -555,6 +556,10 @@
     base:LayerBase;
 }
 
+table PreluLayer {
+    base:LayerBase;
+}
+
 union Layer {
     ActivationLayer,
     AdditionLayer,
@@ -596,7 +601,8 @@
     MergeLayer,
     SwitchLayer,
     ConcatLayer,
-    SpaceToDepthLayer
+    SpaceToDepthLayer,
+    PreluLayer
 }
 
 table AnyLayer {