hwupload_videotoolbox_ios: move mipmap generation at the end of vt_ios_dr_map_frame()
hwupload_videotoolbox_ios: move mipmap generation at the end of vt_ios_dr_map_frame()

gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl