net/rds/Kconfig: Correct the RDS depends

Remove prefix 'CONFIG_' from CONFIG_IPV6

Fixes: ba7d7e2677c0 ("net/rds/Kconfig: RDS should depend on IPV6")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/Kconfig

@@ -1,7 +1,7 @@
 
 config RDS
 	tristate "The RDS Protocol"
-	depends on INET && CONFIG_IPV6
+	depends on INET && IPV6
 	---help---
 	  The RDS (Reliable Datagram Sockets) protocol provides reliable,
 	  sequenced delivery of datagrams over Infiniband or TCP.