Test `bootconfig` from current kernel doesn't get out of sync with `bootconfig` from SDK

[zmrow]

We currently package the bootconfig CLI from the current version of the 5.10 kernel. Though bootconfig doesn't receive a ton of updates, it does pull in some header files from the kernel, so we need to make sure that newer kernel versions are compatible with the output of our particular bootconfig.

Possible options:

• Boot a variant with an initrd generated with bootconfig (perhaps via QEMU?) and ensure compatibility
• (Preferable) Generate an initrd with bootconfig from the SDK, and then use the bootconfig from our current kernel version to output the bootconfig from the previously generated initrd. This would require us to compile the bootconfig from our current kernel somewhere we could find it.