IVGCVSW-4622 Add NEON FILL Workload

* Added Neon workload for Fill Operator
* Enabled Fill operator tests on Neon
* NEFill function does not have validate() function yet
  IsLayerSupported() function return true at the moment
* Added INT32 supported type for CpuRef

Signed-off-by: Sadik Armagan <sadik.armagan@arm.com>
Change-Id: I17bf5ec13750f46322a30653e15ba2a514f61f08
diff --git a/src/backends/reference/RefLayerSupport.cpp b/src/backends/reference/RefLayerSupport.cpp
index e13a2e2..18b36a5 100644
--- a/src/backends/reference/RefLayerSupport.cpp
+++ b/src/backends/reference/RefLayerSupport.cpp
@@ -867,10 +867,11 @@
 
     bool supported = true;
 
-    std::array<DataType,2> supportedTypes =
+    std::array<DataType,3> supportedTypes =
     {
         DataType::Float32,
-        DataType::Float16
+        DataType::Float16,
+        DataType::Signed32
     };
 
     supported &= CheckSupportRule(TypeAnyOf(input, supportedTypes), reasonIfUnsupported,