act_connmark: fix dependencies better

NET_ACT_CONNMARK fails to build if NF_CONNTRACK_MARK is disabled,
and d7924450 ("act_connmark: Add missing dependency on
NF_CONNTRACK_MARK") fixed that case, but missed the cased where
NF_CONNTRACK is a loadable module.

This adds the second dependency to ensure that NET_ACT_CONNMARK
can only be built-in if NF_CONNTRACK is also part of the kernel
rather than a loadable module.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/Kconfig

@@ -713,7 +713,7 @@ config NET_ACT_BPF
 config NET_ACT_CONNMARK
         tristate "Netfilter Connection Mark Retriever"
         depends on NET_CLS_ACT && NETFILTER && IP_NF_IPTABLES
-        depends on NF_CONNTRACK_MARK
+        depends on NF_CONNTRACK && NF_CONNTRACK_MARK
         ---help---
 	  Say Y here to allow retrieving of conn mark