[Comgr] Clean up HIP options

HIP by default should be compiled with -nogpuinc to not
rely on unavailable clang headers

Also we can replace --cuda-device-only with the synonymous
--offload-device-only

Finally, we can remove the hard-coded std=c++11, and instead rely
on the clang default (currently c++17)

Change-Id: I68ba0226013dad6708862987eb66a4e7487cb23b

Author: lamb-j

amd/comgr/src/comgr-compiler.cpp

@@ -1056,8 +1056,8 @@ amd_comgr_status_t AMDGPUCompiler::addCompilationFlags() {
     break;
   case AMD_COMGR_LANGUAGE_HIP:
     Args.push_back("hip");
-    Args.push_back("-std=c++11");
-    Args.push_back("--cuda-device-only");
+    Args.push_back("-nogpuinc");
+    Args.push_back("--offload-device-only");
     Args.push_back("-isystem");
     Args.push_back(ROCMIncludePath.c_str());
     Args.push_back("-isystem");