[NETROM/AX.25/ROSE]: Remove useless tests

Remove error tests that have already been performed by the caller.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index f4578c7..02b1ab5 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -1187,9 +1187,7 @@
 	}
 
 	case SIOCGSTAMP:
-		ret = -EINVAL;
-		if (sk != NULL)
-			ret = sock_get_timestamp(sk, argp);
+		ret = sock_get_timestamp(sk, argp);
 		release_sock(sk);
 		return ret;