net/udp: Fix a copy-paste error that could effect networking when both IPv4 and IPv6 are enabled.

net/udp/udp_psock_sendto.c

@@ -194,7 +194,7 @@ static inline void sendto_ipselect(FAR struct net_driver_s *dev,
       /* Select the IPv6 domain */
 
       DEBUGASSERT(psock->s_domain == PF_INET6);
-      udp_ipv4_select(dev);
+      udp_ipv6_select(dev);
     }
 }
 #endif