copier: remove ipcgtw copy case

ipcgtw copy is empty, due to ipcgtw device will be removed, so
remove its copy function.

Signed-off-by: Baofeng Tian <baofeng.tian@intel.com>

src/audio/copier/copier.c

@@ -1417,7 +1417,7 @@ static int do_endpoint_copy(struct comp_dev *dev)
 		default:
 			break;
 		}
-		return cd->endpoint[0]->drv->ops.copy(cd->endpoint[0]);
+		return 0;
 	}
 }