[HIPIFY] Get rid of setting '--cuda-gpu-arch='

[Reasons]
+ We don't compile kernel code at least for now as HIP kernel syntax is almost equal CUDA's;
+ clang always includes PTX in its binaries, so e.g. a binary compiled with --cuda-gpu-arch= would be forwards-compatible with e.g. sm_35 GPUs.

tests/hipify-clang/lit.cfg

@@ -60,7 +60,7 @@ if obj_root is not None:
     config.environment['PATH'] = path
 
 hipify_path = obj_root
-clang_args = "-v --cuda-gpu-arch=sm_30 --cuda-path='%s'"
+clang_args = "-v --cuda-path='%s'"
 
 if sys.platform in ['win32']:
     run_test_ext = ".bat"