IVGCVSW-3478 Refactor armnn to make new Lstm parameters available in android-nn-driver through ILayerSupport.h

!android-nn-driver:1506

Signed-off-by: Ferran Balaguer <ferran.balaguer@arm.com>
Change-Id: Ia9904bd355c72a84f07d0a26faf143a4d6aead9c
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7c163dc..dbb212f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -323,6 +323,7 @@
     src/armnn/layers/TransposeConvolution2dLayer.cpp
     src/armnn/layers/TransposeConvolution2dLayer.hpp
     src/armnn/BackendSettings.hpp
+    src/armnn/BackendHelper.cpp
     src/armnn/CompatibleTypes.hpp
     src/armnn/Descriptors.cpp
     src/armnn/DeviceSpec.hpp