Remove hip-hcc codes: Part three

1.Rename include/hip/hcc_detail/ as include/hip/amd_detail/

2.Rename include/hip/nvcc_detail/ as include/hip/nvidia_detail/

3.Create __HIP_PLATFORM_AMD__ to replace __HIP_PLATFORM_HCC__

4.Create __HIP_PLATFORM_NVIDIA__ to replace __HIP_PLATFORM_NVCC__

After hcc_detail, nvcc_detail, __HIP_PLATFORM_HCC__ and __HIP_PLATFORM_NVCC__
have been removed from upstream, they will be removed from hip runtime.

Change-Id: I1ae457effd739d6c25bca203c1724b026be21fce

hipamd/samples/0_Intro/bit_extract/README.md

@@ -1,6 +1,6 @@
 # bit_extract
 
-Show an application written directly in HIP which uses platform-specific check on __HIP_PLATFORM_HCC__ to enable use of 
+Show an application written directly in HIP which uses platform-specific check on __HIP_PLATFORM_AMD__ to enable use of
 an instruction that only exists on the HCC platform.
 
 See related [blog](http://gpuopen.com/platform-aware-coding-inside-hip/) demonstrating platform specialization.