va/test: return a value to silence compiler waring

Signed-off-by: Xiang, Haihao <haihao.xiang@intel.com>

test/encode/h264encode_x11.c

@@ -93,7 +93,7 @@ static int display_surface(int frame_id, int *exit_encode)
         }	
     }	
 
-    return;
+    return 0;
 }
 
 #include "h264encode_common.c"

test/putsurface/putsurface_x11.c

@@ -161,6 +161,8 @@ static int check_window_event(void *win_display, void *drawable, int *width, int
         printf("Scale window to %dx%d\n", width, height);
     }
 #endif
+
+    return 0;
 }