[miopen-hip] Make sure clang-offload-bundler is used (#417)
The CMake logic currently only looks for `clang-offload-bundler`, if `MIOPEN_HIP_COMPILER`
is clang++. If undefined, it falls back to hipcc, which results in `extractkernel` being used.
Upstream miopen is built with `clang-offload-bundler` support, according to
`/opt/rocm-3.7.0/miopen/include/miopen/config.h` in the official docker container.
With this change in place, the config headers are essentially the same:
```patch
--- build/include/miopen/config.h 2020-09-12 00:01:00.140410402 +0200
+++ upstream/include/miopen/config.h 2020-09-11 23:34:40.735846511 +0200
@@ -49,7 +49,7 @@
// clang-format off
#define HIP_PACKAGE_VERSION_MAJOR 3
#define HIP_PACKAGE_VERSION_MINOR 7
-#define HIP_PACKAGE_VERSION_PATCH 20364
+#define HIP_PACKAGE_VERSION_PATCH 20315
// clang-format on
// clang-format off
@@ -68,8 +68,8 @@
#define MIOPEN_USE_RNE_BFLOAT16 1
#define MIOPEN_AMDGCN_ASSEMBLER "/opt/rocm/llvm/bin/clang"
-#define HIP_OC_COMPILER "/opt/rocm/bin/clang-ocl"
-#define MIOPEN_HIP_COMPILER "/opt/rocm/llvm/bin/clang++"
+#define HIP_OC_COMPILER "/opt/rocm-3.7.0/bin/clang-ocl"
+#define MIOPEN_HIP_COMPILER "/opt/rocm-3.7.0/llvm/bin/clang++"
/* #undef EXTRACTKERNEL_BIN */
#define MIOPEN_OFFLOADBUNDLER_BIN "/opt/rocm/llvm/bin/clang-offload-bundler"
#define MIOPEN_CACHE_DIR "~/.cache/miopen/"
```