seabios for lkvm

Here is the new patch based on Asias's work.
It's now based en seabios's HEAD making it easier to test.

Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: William Dauchy <william@gandi.net>
Signed-off-by: Pekka Enberg <penberg@kernel.org>