netfilter: kill remnants of ulog targets

The ulog targets were recently killed. A few references to the Kconfig
macros CONFIG_IP_NF_TARGET_ULOG and CONFIG_BRIDGE_EBT_ULOG were left
untouched. Kill these too.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>