cnic: Replace rcu_dereference() with rcu_access_pointer()

The "rcu_dereference()" calls are used directly in conditions.
Since their return values are never dereferenced it is recommended to use
"rcu_access_pointer()" instead of "rcu_dereference()".
Therefore, this patch makes the replacements.

The following Coccinelle semantic patch was used:
@@
@@

(
 if(
 (<+...
- rcu_dereference
+ rcu_access_pointer
  (...)
  ...+>)) {...}
|
 while(
 (<+...
- rcu_dereference
+ rcu_access_pointer
  (...)
  ...+>)) {...}
)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/cnic.c

@@ -383,7 +383,7 @@ static int cnic_iscsi_nl_msg_recv(struct cnic_dev *dev, u32 msg_type,
 			break;
 
 		rcu_read_lock();
-		if (!rcu_dereference(cp->ulp_ops[CNIC_ULP_L4])) {
+		if (!rcu_access_pointer(cp->ulp_ops[CNIC_ULP_L4])) {
 			rc = -ENODEV;
 			rcu_read_unlock();
 			break;
@@ -527,7 +527,7 @@ int cnic_unregister_driver(int ulp_type)
 	list_for_each_entry(dev, &cnic_dev_list, list) {
 		struct cnic_local *cp = dev->cnic_priv;
 
-		if (rcu_dereference(cp->ulp_ops[ulp_type])) {
+		if (rcu_access_pointer(cp->ulp_ops[ulp_type])) {
 			pr_err("%s: Type %d still has devices registered\n",
 			       __func__, ulp_type);
 			read_unlock(&cnic_dev_lock);
@@ -575,7 +575,7 @@ static int cnic_register_device(struct cnic_dev *dev, int ulp_type,
 		mutex_unlock(&cnic_lock);
 		return -EAGAIN;
 	}
-	if (rcu_dereference(cp->ulp_ops[ulp_type])) {
+	if (rcu_access_pointer(cp->ulp_ops[ulp_type])) {
 		pr_err("%s: Type %d has already been registered to this device\n",
 		       __func__, ulp_type);
 		mutex_unlock(&cnic_lock);