ipv6: fix kabi for mc_forwarding in struct ipv6_devconf

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5GL1Z
CVE: NA

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Making mc_forwarding atomic breaks the KABI of struct ipv6_devconf.
This patch uses KABI_REPLACE to fix it.
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

include/linux/ipv6.h

@@ -51,7 +51,7 @@ struct ipv6_devconf {
 	__s32		use_optimistic;
 #endif
 #ifdef CONFIG_IPV6_MROUTE
-	atomic_t	mc_forwarding;
+	KABI_REPLACE(__s32 mc_forwarding, atomic_t mc_forwarding)
 #endif
 	__s32		disable_ipv6;
 	__s32		drop_unicast_in_l2_multicast;