winex11: Correct compile without vulkan support.

Signed-off-by: Alistair Leslie-Hughes <leslie_alistair@hotmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/winex11.drv/vulkan.c

@@ -626,4 +626,8 @@ const struct vulkan_funcs *get_vulkan_driver(UINT version)
     return NULL;
 }
 
+void wine_vk_surface_destroy(HWND hwnd)
+{
+}
+
 #endif /* SONAME_LIBVULKAN */