Add hipclang amdgcn functions

These are moving from hipclang in device library to hip headers. These are required for the functionality of HIPclang project.

src/device_util.cpp

@@ -144,9 +144,6 @@ __device__ void* __hip_hc_memset(void* dst, uint8_t val, size_t size) {
     return dst;
 }
 
-__device__ long long int clock64() { return (long long int)hc::__cycle_u64(); };
-__device__ clock_t clock() { return (clock_t)hc::__cycle_u64(); };
-
 // abort
 __device__ void abort() { return hc::abort(); }
 
@@ -203,11 +200,7 @@ __host__ __device__ int max(int arg1, int arg2) {
     return (int)(hc::precise_math::fmax((float)arg1, (float)arg2));
 }
 
-__device__ void* __get_dynamicgroupbaseptr() {
-    return hc::get_dynamic_group_segment_base_pointer();
-}
-
 __host__ void* __get_dynamicgroupbaseptr() { return nullptr; }
 
 
-__device__ void __threadfence_system(void) { std::atomic_thread_fence(std::memory_order_seq_cst); }
+__device__ void __threadfence_system(void) { std::atomic_thread_fence(std::memory_order_seq_cst); }