message: general/rocm.hpp double defines fix
diff: #define MFEM_THREAD_ID(k) hipThreadIdx_ ##k
  #define MFEM_THREAD_SIZE(k) hipBlockDim_ ##k
  #define MFEM_FOREACH_THREAD(i,k,N) for(int i=hipThreadIdx_ ##k; i<N; i+=hipBlockDim_ ##k)
  -#else
  -#define MFEM_SHARED
  -#define MFEM_SYNC_THREAD
  -#define MFEM_THREAD_ID(k) 0
  -#define MFEM_THREAD_SIZE(k) 1
  -#define MFEM_FOREACH_THREAD(i,k,N) for(int i=0; i<N; i++)
  #endif
  