x86: Add reboot fixup for SBC-fitPC2

The CompuLab SBC-fitPC2 board needs to reboot via BIOS.

Signed-off-by: Denis Turischev <denis@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>