buildroot

website: remove dead udhcp link

The udhcp.busybox.net site is gone, it's now pointing to bugzilla.
udhcp has been a part of busybox for some time now.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>