deps/Linux: update to v6.1 and switch to a self-decompressing EFI binary on arm64

Linux 6.1 brought the ability to self-decompress at boot time on arm64, like we could do on amd64!

This means we do not need to decompress the kernel anymore in u-boot before booting it, which should resolve the biggest issue I have been having booting boot2container on ARM Single Board Computers!

I'll get back to it and write a guide soon :)