MLCE-530 Add support for UnidirectionalSequenceLstm to RefWorkload

 * Add implementation of IsUnidirectionalSequenceLstmSupported to RefLayerSupport
 * Add RefUnidirectionalSequenceLstmWorkload
 * Refactor Lstm to be able to use for Lstm and SequenceLstm
 * Unit tests

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: Ibc066d213213a11b955dfefbe518de643298ba0c
diff --git a/src/backends/reference/workloads/RefWorkloads.hpp b/src/backends/reference/workloads/RefWorkloads.hpp
index afe63d1..d3ae58e 100644
--- a/src/backends/reference/workloads/RefWorkloads.hpp
+++ b/src/backends/reference/workloads/RefWorkloads.hpp
@@ -69,6 +69,7 @@
 #include "RefSpaceToDepthWorkload.hpp"
 #include "RefTransposeConvolution2dWorkload.hpp"
 #include "RefTransposeWorkload.hpp"
+#include "RefUnidirectionalSequenceLstmWorkload.hpp"
 #include "RefWorkloadUtils.hpp"
 #include "Resize.hpp"
 #include "Softmax.hpp"