[SYCL] refactor (#6408)

* seperate lower precision GEMM from the main files

* fix workgroup size hardcode

ggml-sycl/convert.hpp

@@ -0,0 +1,27 @@
+//
+// MIT license
+// Copyright (C) 2024 Intel Corporation
+// SPDX-License-Identifier: MIT
+//
+
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+
+#ifndef GGML_SYCL_CONVERT_HPP
+#define GGML_SYCL_CONVERT_HPP
+
+#include "common.hpp"
+
+template <typename T>
+using to_t_sycl_t = void (*)(const void *__restrict__ x, T *__restrict__ y,
+                             int k, dpct::queue_ptr stream);
+typedef to_t_sycl_t<float> to_fp32_sycl_t;
+typedef to_t_sycl_t<sycl::half> to_fp16_sycl_t;
+
+to_fp16_sycl_t ggml_get_to_fp16_sycl(ggml_type type);
+to_fp32_sycl_t ggml_get_to_fp32_sycl(ggml_type type);
+
+#endif // GGML_SYCL_CONVERT_HPP