net: netfilter: move bpf_ct_set_nat_info kfunc in nf_nat_bpf.c

Remove circular dependency between nf_nat module and nf_conntrack one
moving bpf_ct_set_nat_info kfunc in nf_nat_bpf.c

Fixes: 0fabd2aa199f ("net: netfilter: add bpf_ct_set_nat_info kfunc helper")
Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Yauheni Kaliuta <ykaliuta@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/51a65513d2cda3eeb0754842e8025ab3966068d8.1664490511.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 06df49e..0f060d1 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -60,6 +60,12 @@
 nf_nat-$(CONFIG_NF_NAT_REDIRECT) += nf_nat_redirect.o
 nf_nat-$(CONFIG_NF_NAT_MASQUERADE) += nf_nat_masquerade.o
 
+ifeq ($(CONFIG_NF_NAT),m)
+nf_nat-$(CONFIG_DEBUG_INFO_BTF_MODULES) += nf_nat_bpf.o
+else ifeq ($(CONFIG_NF_NAT),y)
+nf_nat-$(CONFIG_DEBUG_INFO_BTF) += nf_nat_bpf.o
+endif
+
 # NAT helpers
 obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_amanda.o
 obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o