ulogd: only for kernels <= 3.16.x

The ulog netfilter target has been deprecated for some time and removed
in kernels >= 3.17.x so limit it to older headers. Fixes:
http://autobuild.buildroot.net/results/9ca/9ca43764c7363f9a00b8a0c7df20a492c00088b5/



Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>