Replace __HIP_PLATFORM_AMD__ to use internal macro (#712)

Replacing most of checks for `__HIP_PLATFORM_AMD__` with
`MSCCLPP_DEVICE_HIP` for device and `MSCCLPP_USE_ROCM` for host source
file.

python/csrc/gpu_utils_py.cpp

@@ -16,7 +16,7 @@ using namespace mscclpp;
 constexpr int BYTE_BITS = 8;
 
 static DLDeviceType getDeviceType() {
-#if defined(__HIP_PLATFORM_AMD__)
+#if defined(MSCCLPP_USE_ROCM)
   return kDLROCM;
 #else
   return kDLCUDA;