tipc: add missing attribute validation for MTU property

Add missing attribute validation for TIPC_NLA_PROP_MTU
to the netlink policy.

Fixes: 901271e0 ("tipc: implement configuration of UDP media MTU")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/netlink.c

@@ -116,6 +116,7 @@ const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
 	[TIPC_NLA_PROP_PRIO]		= { .type = NLA_U32 },
 	[TIPC_NLA_PROP_TOL]		= { .type = NLA_U32 },
 	[TIPC_NLA_PROP_WIN]		= { .type = NLA_U32 },
+	[TIPC_NLA_PROP_MTU]		= { .type = NLA_U32 },
 	[TIPC_NLA_PROP_BROADCAST]	= { .type = NLA_U32 },
 	[TIPC_NLA_PROP_BROADCAST_RATIO]	= { .type = NLA_U32 }
 };