dhcp6: extend link timeout
dhcp6: extend link timeout

Extends the timeout waiting for a non-tentative IPv6 address.

If c.Timeout is too short, no DHCPv6 lease will be attempted at all.
Internally, this messed us up at 3 seconds. For now, let's just give a
default timeout.

Signed-off-by: Chris Koch <cd2178739c1fb8f241acc6c7bd5abe02c150d7e5@google.com>

hugelgupf/u-root,GanShun/u-root,u-root/u-root,u-root/u-root,hugelgupf/u-root,GanShun/u-root,hugelgupf/u-root,hugelgupf/u-root,u-root/u-root,GanShun/u-root