this is the submit of the patch discussed yesterday to compile the sit
driver as a seperate module.

changes to yesterday:
- default select changed to y in Kconfig
- added ifdefs to net/ipv6/addrconf.c
  (this part is big, to keep the patches around 100 lines the
   addrconf.c changes are posted in a seperate patch)

Signed-off-by: Joerg Roedel <joro-lkml@zlug.org>