Add gridwise gemm pipeline v1/v2 selector

include/ck/tensor_operation/gpu/grid/gridwise_gemm_pipeline_selector.hpp

+// SPDX-License-Identifier: MIT
+// Copyright (c) 2018-2022, Advanced Micro Devices, Inc. All rights reserved.
+
+#pragma once
+
+#include "ck/tensor_operation/gpu/grid/gridwise_gemm_pipeline_v1.hpp"
+#include "ck/tensor_operation/gpu/grid/gridwise_gemm_pipeline_v2.hpp"
+
+namespace ck {
+
+template <index_t PipelineVersion,
+          index_t NumPrefetch     = 1,
+          LoopScheduler LoopSched = LoopScheduler::Default>
+constexpr auto GridwiseGemmPipeline_Selector()
+{
+    if constexpr(PipelineVersion == 1)
+    {
+        return GridwiseGemmPipeline_v1_Selector<NumPrefetch, LoopSched>{};
+    }
+    else if constexpr(PipelineVersion == 2)
+    {
+        return GridwiseGemmPipeline_v2{};
+    }
+    else
+    {
+        // put some error message here
+    }
+}
+
+} // namespace ck