IVGCVSW-2915 Add Merge Layer and no-op factory method

Change-Id: I54549671e0d3b207904cf9796a843eb2b0a631f7
Signed-off-by: Nattapat Chaimanowong <nattapat.chaimanowong@arm.com>
diff --git a/src/armnnSerializer/ArmnnSchema.fbs b/src/armnnSerializer/ArmnnSchema.fbs
index 3aa644d..8b275b6 100644
--- a/src/armnnSerializer/ArmnnSchema.fbs
+++ b/src/armnnSerializer/ArmnnSchema.fbs
@@ -118,7 +118,8 @@
     DetectionPostProcess = 33,
     Lstm = 34,
     Quantize = 35,
-    Dequantize = 36
+    Dequantize = 36,
+    Merge = 37
 }
 
 // Base layer table to be used as part of other layers
@@ -524,6 +525,10 @@
     base:LayerBase;
 }
 
+table MergeLayer {
+    base:LayerBase;
+}
+
 union Layer {
     ActivationLayer,
     AdditionLayer,
@@ -561,7 +566,8 @@
     DetectionPostProcessLayer,
     LstmLayer,
     QuantizeLayer,
-    DequantizeLayer
+    DequantizeLayer,
+    MergeLayer
 }
 
 table AnyLayer {