[IPV6]: Dumb typo in generic csum_ipv6_magic()

... duh

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h
index 68e2b32..bc1b0fd 100644
--- a/include/net/ip6_checksum.h
+++ b/include/net/ip6_checksum.h
@@ -87,7 +87,7 @@
 	carry = (sum < uproto);
 	sum += carry;
 
-	return csum_fold((__force __wsum)csum);
+	return csum_fold((__force __wsum)sum);
 }
 
 #endif