如何在我的docker buildx构建器中添加对mips的支持？

Question

我已经创建了一个buildx生成器，但是缺少mipsel支持。我认为它也应该支持所有拱门qemu的支持。

$ docker buildx create --name mybuilder
mybuilder
$ docker buildx use mybuilder
$ docker buildx inspect --bootstrap
[+] Building 6.8s (1/1) FINISHED                                                                                    
 => [internal] booting buildkit                                                                                6.8s
 => => pulling image moby/buildkit:buildx-stable-1                                                             5.9s
 => => creating container buildx_buildkit_mybuilder0                                                          0.9s
Name:   mybuilder
Driver: docker-container

Nodes:
Name:      mybuilder0
Endpoint:  unix:///var/run/docker.sock
Status:    running
Platforms: linux/amd64, linux/arm64, linux/ppc64le, linux/s390x, linux/386, linux/arm/v7, linux/arm/v6

为什么mipsel（我感兴趣的体系结构）不在列表中？