netfilter: nf_tables: fix endian mismatch in return type

harmless, but it avoids sparse warnings:

nf_tables_api.c:2813:16: warning: incorrect type in return expression (different base types)
nf_tables_api.c:2863:47: warning: incorrect type in argument 3 (different base types)
nf_tables_api.c:3524:47: warning: incorrect type in argument 3 (different base types)
nf_tables_api.c:3538:55: warning: incorrect type in argument 3 (different base types)

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -2830,7 +2830,7 @@ static int nf_msecs_to_jiffies64(const struct nlattr *nla, u64 *result)
 	return 0;
 }
 
-static u64 nf_jiffies64_to_msecs(u64 input)
+static __be64 nf_jiffies64_to_msecs(u64 input)
 {
 	u64 ms = jiffies64_to_nsecs(input);