netfilter: xt_NFLOG is dependant of nfnetlink_log

The patch "don't call nf_log_packet in NFLOG module" make xt_NFLOG
dependant of nfnetlink_log. This patch forces the dependencies to fix
compilation in case only xt_NFLOG compilation was asked and modifies the
help message accordingly to the change.
Signed-off-by: NEric Leblond <eric@inl.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netfilter/Kconfig

@@ -373,11 +373,10 @@ config NETFILTER_XT_TARGET_MARK
 config NETFILTER_XT_TARGET_NFLOG
 	tristate '"NFLOG" target support'
 	default m if NETFILTER_ADVANCED=n
+	select NETFILTER_NETLINK_LOG
 	help
 	  This option enables the NFLOG target, which allows to LOG
-	  messages through the netfilter logging API, which can use
-	  either the old LOG target, the old ULOG target or nfnetlink_log
-	  as backend.
+	  messages through nfnetlink_log.
 
 	  To compile it as a module, choose M here.  If unsure, say N.