fix void pointer cast bug

src/ngraph/runtime/gpu/gpu_external_function.cpp

@@ -511,7 +511,7 @@ void runtime::gpu::GPU_ExternalFunction::compile()
                 {
                     stringstream ss;
                     ss << "((" << tensor->get_element_type().c_type_string()
-                       << "*)(pool_base_ptr + " << tensor->get_pool_offset() << "))";
+                       << "*)((char *)pool_base_ptr + " << tensor->get_pool_offset() << "))";
                     m_variable_name_map[tensor->get_name()] = ss.str();
                 }
             }

src/ngraph/runtime/gpu/gpu_util.hpp

@@ -24,7 +24,7 @@ namespace ngraph
         {
             void print_gpu_f32_tensor(void* p, size_t element_count, size_t element_size);
             void check_cuda_errors(CUresult err);
-            void** create_gpu_buffer(size_t buffer_size);
+            void* create_gpu_buffer(size_t buffer_size);
             void cuda_memcpyDtD(void* d, void* s, size_t element_count, size_t element_size);
             void cuda_memcpyHtD(void* d, void* s, size_t buffer_size);
         }