Add support for the PXELINUX options 209 ("ConfigFile") and 210
("PathPrefix") in the DHCPv6 client.
See also: RFC5071, "Dynamic Host Configuration Protocol Options Used by
PXELINUX".
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>