Some BIOSes are reported to corrupt %ebx when using INT 15,2401 (see
http://opensolaris.org/jive/thread.jspa?messageID=377026). Guard
against this by preserving all (non-segment) registers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
libflat no longer has anything to do with flat real mode; it handles
only the A20 gate. Update library name to match.
Signed-off-by: Michael Brown <mcb30@ipxe.org>