loader.efi: Make framebuffer commands available for arm64

[manu]

Summary

Move framebuffer.{c,h} to sys/boot/efi/loader and add the efifb
related metadata and pass it to the kernel

Test Plan

Tested On: Pine64

[imp]

This looks good. One note for posterity that's likely a big swamp to drain so isn't gating this commit.

sys/boot/efi/loader/bootinfo.c

251 ↗

(On Diff #34230)

This is fine for this commit, however...

I'm starting to think that we need to overhaul the loader's #defines for stuff like this. LOADER_FOO_SUPPORT isn't quite right.

Somethign to think about.

[andrew]

sys/boot/efi/loader/bootinfo.c

251 ↗

(On Diff #34230)

Do we even need this #if?

[manu]

sys/boot/efi/loader/bootinfo.c

251 ↗

(On Diff #34230)

For now yes and I didn't tested on arm (I will commit with defined(arm) removed.
After that I'm not sure we need it.