Disable device code for gcc in hip_memory.h

These device code should only be seen by HCC or hip-clang. They causd build failure
for HIP-VDI runtime and should be disabled for gcc.

include/hip/hcc_detail/hip_memory.h

@@ -39,6 +39,8 @@ THE SOFTWARE.
 
 #define __HIP_SIZE_OF_HEAP (__HIP_NUM_PAGES * __HIP_SIZE_OF_PAGE)
 
+#if __HCC__ || __HIP__
+
 __attribute__((weak)) __device__ char __hip_device_heap[__HIP_SIZE_OF_HEAP];
 __attribute__((weak)) __device__
     uint32_t __hip_device_page_flag[__HIP_NUM_PAGES];
@@ -102,4 +104,6 @@ extern "C" inline __device__ void* __hip_free(void* ptr) {
     return nullptr;
 }
 
+#endif
+
 #endif // HIP_INCLUDE_HIP_HCC_DETAIL_HIP_MEMORY_H