The buildhw-x86 blades also can enable serial console for ipmi/sol.
Rework this to handle the fedora case of options not being in
/etc/grub2-efi.cfg anymore.
Also set both serial S0 and S1 enabled, since some hardware seems to use
one and some uses the other.
Signed-off-by: Kevin Fenzi <kevin@scrye.com>