Moved device code to mimic cuda header behavior

1. All fp32, fp64 math device/host functions should be in math_functions.h/.cpp
2. All fp32, fp64 fast math intrinsics for device/host functions should be in device_functions.h/.cpp
3. All the device code implementations should be in device_util.h/.cpp
4. Hence, made changes appropriately by moving code and creating new header files
5. Added math_functions.cpp/.h
6. Changed #ifndef signature to make sure no conflicts between headers with same names in hip/hip_runtime.h and hip/hcc_detail/hip_runtime.h
7. Changed tests to fit the code changes, making them to include appropriate headers
8. Added math_functions.cpp to CMakeLists.txt
9. Some of the tests are still broken, mostly host math functions will fix them in next commit
10. TODO: FIX compilation issues for host math functions

Change-Id: I7a17637d7e294a7d224ffba932c1a08668febd26

include/hip/math_functions.h

@@ -0,0 +1,49 @@
+/*
+Copyright (c) 2015-2017 Advanced Micro Devices, Inc. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+//! HIP = Heterogeneous-compute Interface for Portability
+//!
+//! Define a extremely thin runtime layer that allows source code to be compiled unmodified
+//! through either AMD HCC or NVCC.   Key features tend to be in the spirit
+//! and terminology of CUDA, but with a portable path to other accelerators as well:
+//
+//! Both paths support rich C++ features including classes, templates, lambdas, etc.
+//! Runtime API is C
+//! Memory management is based on pure pointers and resembles malloc/free/copy.
+//
+//! hip_runtime.h     : includes everything in hip_api.h, plus math builtins and kernel launch macros.
+//! hip_runtime_api.h : Defines HIP API.  This is a C header file and does not use any C++ features.
+
+#pragma once
+
+// Some standard header files, these are included by hc.hpp and so want to make them avail on both
+// paths to provide a consistent include env and avoid "missing symbol" errors that only appears
+// on NVCC path:
+
+
+#if defined(__HIP_PLATFORM_HCC__) && !defined (__HIP_PLATFORM_NVCC__)
+#include <hip/hcc_detail/math_functions.h>
+#elif defined(__HIP_PLATFORM_NVCC__) && !defined (__HIP_PLATFORM_HCC__)
+#include <hip/nvcc_detail/math_functions.h>
+#else
+#error("Must define exactly one of __HIP_PLATFORM_HCC__ or __HIP_PLATFORM_NVCC__");
+#endif