[IPV6]: Dumb typo in generic csum_ipv6_magic()

... duh
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ip6_checksum.h

@@ -87,7 +87,7 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 	carry = (sum < uproto);
 	sum += carry;
 
-	return csum_fold((__force __wsum)csum);
+	return csum_fold((__force __wsum)sum);
 }
 
 #endif