update microblaze qemu boards to 3.14

- fix networking in Qemu using a small patch
- disable DTS, because linux.bin does not include any DTB the
  default Qemu included DTB is used and this is okay and works fine

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Tested-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>