ipv6: Use result arg in fib_lookup_arg consistently

arg.result is sometimes used as fib6_result and sometimes used to
hold the rt6_info. Add rt6_info to fib6_result and make the use
of arg.result consistent through ipv6 rules.

The rt6 entry is filled in for lookups returning a dst_entry, but not
for direct fib_lookups that just want a fib6_info.

Fixes: effda4dd97e8 ("ipv6: Pass fib6_result to fib lookups")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 5a4a67b..4010573 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -195,6 +195,7 @@ struct fib6_result {
 	struct fib6_info	*f6i;
 	u32			fib6_flags;
 	u8			fib6_type;
+	struct rt6_info		*rt6;
 };
 
 #define for_each_fib6_node_rt_rcu(fn)					\