IVGCVSW-1207 - Remove typing from ClMultiplicationWorkload

Don't need this now as it uses the compute library validation function,
and all of the code for the supported types is identical.

Adds Uint8 support to Cl backend, and unit test cases.

Change-Id: I35d4edacc1aca241e95d1b19ae525a23d9513c99
diff --git a/src/backends/cl/ClWorkloadFactory.cpp b/src/backends/cl/ClWorkloadFactory.cpp
index 46a9655..685696c 100644
--- a/src/backends/cl/ClWorkloadFactory.cpp
+++ b/src/backends/cl/ClWorkloadFactory.cpp
@@ -170,7 +170,7 @@
 std::unique_ptr<armnn::IWorkload> ClWorkloadFactory::CreateMultiplication(
     const MultiplicationQueueDescriptor& descriptor, const WorkloadInfo& info) const
 {
-    return MakeWorkload<ClMultiplicationFloatWorkload, ClMultiplicationFloatWorkload>(descriptor, info);
+    return std::make_unique<ClMultiplicationWorkload>(descriptor, info);
 }
 
 std::unique_ptr<armnn::IWorkload> ClWorkloadFactory::CreateDivision(