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/ib_sysctl.c b/net/rds/ib_sysctl.c
index 03f01cb..c070524 100644
--- a/net/rds/ib_sysctl.c
+++ b/net/rds/ib_sysctl.c
@@ -135,7 +135,7 @@
 int __init rds_ib_sysctl_init(void)
 {
 	rds_ib_sysctl_hdr = register_sysctl_paths(rds_ib_sysctl_path, rds_ib_sysctl_table);
-	if (rds_ib_sysctl_hdr == NULL)
+	if (!rds_ib_sysctl_hdr)
 		return -ENOMEM;
 	return 0;
 }