IVGCVSW-2510 Ref workload implementation for Gather operator
 * add implemenentation for GatherQueueDescriptor validate function
 * add FirstInputTypedWorkload to allow type check on the first input tensor only
 * add ref workload implemenentation for float and uint8
 * add Gather layer support in Ref
 * unit tests

Change-Id: I4578a3211f11d24aa29d15bcf7f45b0445bcd1ee
diff --git a/src/backends/reference/backend.mk b/src/backends/reference/backend.mk
index 84f15c9..8dd6a51 100644
--- a/src/backends/reference/backend.mk
+++ b/src/backends/reference/backend.mk
@@ -18,6 +18,7 @@
         workloads/Debug.cpp \
         workloads/ElementwiseFunction.cpp \
         workloads/FullyConnected.cpp \
+        workloads/Gather.cpp \
         workloads/Mean.cpp \
         workloads/Pad.cpp \
         workloads/Pooling2d.cpp \
@@ -42,6 +43,7 @@
         workloads/RefFloorFloat32Workload.cpp \
         workloads/RefFullyConnectedFloat32Workload.cpp \
         workloads/RefFullyConnectedUint8Workload.cpp \
+        workloads/RefGatherWorkload.cpp \
         workloads/RefL2NormalizationFloat32Workload.cpp \
         workloads/RefLstmFloat32Workload.cpp \
         workloads/RefMeanFloat32Workload.cpp \