fix to support multiple GPUs, fix set single device, unify id/device_id/device_index

Author: NeoZhangJianyu

ggml/include/ggml-sycl.h

@@ -34,6 +34,12 @@ GGML_API GGML_CALL void   ggml_sycl_get_device_description(int device, char *des
 GGML_API GGML_CALL int   ggml_backend_sycl_get_device_count();
 GGML_API GGML_CALL void ggml_backend_sycl_get_device_memory(int device, size_t *free, size_t *total);
 
+GGML_API GGML_CALL int ggml_backend_sycl_get_device_index(int device_id);
+GGML_API GGML_CALL void ggml_sycl_set_single_device(int main_gpu_id);
+
+// GGML_API GGML_CALL void ggml_backend_sycl_set_single_device_mode(int main_gpu_id);
+// GGML_API GGML_CALL void ggml_backend_sycl_set_mul_device_mode();
+
 // SYCL doesn't support registering host memory, keep here for reference
 // GGML_API GGML_CALL bool ggml_backend_sycl_register_host_buffer(void * buffer, size_t size);
 // GGML_API GGML_CALL void ggml_backend_sycl_unregister_host_buffer(void * buffer);