stand/efi: Retire i386 support

[imp]

Summary

Remove the i386 ifdefs and files. It never worked.

Sponsored by: Netflix

[imp]

I'm told that my assertions that this never worked may have been in error... I need to explore a bit more before I do this.

[imp]

The last known user hasn't used this in a very long time and has no desire to continue using it.

[kevans]

In D40012#911110, @imp wrote:

The last known user hasn't used this in a very long time and has no desire to continue using it.

With the ongoing actions against i386, no objection at all to removing its efi loader. I'd find it more interesting if it could do amd64 kernels, as there are some machines with 64-bit CPU, 32-bit firmware... but I think those are rare, mostly older Macs maybe.

[manu]

In D40012#911091, @imp wrote:

I'm told that my assertions that this never worked may have been in error... I need to explore a bit more before I do this.

IIRC it kinda worked on the first Intel Minnowboard but this board reached EOL quickly (and I'm not sure that everything needed for it to work was upstreamed).