pxe: add support for ontimeout token

ontimeout is similar to default, but is the selection on menu timeout.
This is how cobbler sets a default. The label default is supposed to be
the default selection when <enter> is pressed. If both default and
ontimeout are set, last one parsed wins.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
1 file changed