RDS: cleanup: remove "== NULL"s and "!= NULL"s in ptr comparisons

Favor "if (foo)" style over "if (foo != NULL)".

Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index aebfecb..63474e1 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -62,7 +62,7 @@
 	struct rds_sock *rs;
 	unsigned long flags;
 
-	if (sk == NULL)
+	if (!sk)
 		goto out;
 
 	rs = rds_sk_to_rs(sk);