IVGCVSW-3640 Add multi-channel TransposeConvolution2d unit tests to CL backend

* Fixed bug in multi-channel test and reference workload implementation
* Enabled multi-channel tests on CL backend

Signed-off-by: Aron Virginas-Tar <Aron.Virginas-Tar@arm.com>
Change-Id: I08bb523bc68d9c93a1012b4f487a5bce36a085b1
diff --git a/src/backends/reference/workloads/TransposeConvolution2d.cpp b/src/backends/reference/workloads/TransposeConvolution2d.cpp
index acbfe0c..52cc18c 100644
--- a/src/backends/reference/workloads/TransposeConvolution2d.cpp
+++ b/src/backends/reference/workloads/TransposeConvolution2d.cpp
@@ -83,7 +83,7 @@
                                     inputDecoder[inputIndex];
 
                                     const unsigned int weightsIndex =
-                                        dataLayoutIndexed.GetIndex(weightsShape, batch, dOutput, yWeights, xWeights);
+                                        dataLayoutIndexed.GetIndex(weightsShape, dOutput, dInput, yWeights, xWeights);
                                     weightsDecoder[weightsIndex];
 
                                     const unsigned int outputIndex =