Firecracker doesn't support big-endian guests
Firecracker doesn't support big-endian guests

Mention in the docs that Firecracker won't compile on big endian
architectures, and it won't run correctly big endian guests.

Signed-off-by: Radu Iliescu <1da0411f1328e856382f4cd8ea7f69638fd635b8@amazon.com>

firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker