PCI: endpoint: Use IS_ERR_OR_NULL() helper function

Use the IS_ERR_OR_NULL() helper instead of open-coding a NULL and an
error pointer checks to simplify the code and improve readability.

No functional changes are intended.

[kwilczynski: commit log]
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

Author: ruanjinjie-eng

drivers/pci/endpoint/pci-epc-core.c

@@ -38,7 +38,7 @@ static int devm_pci_epc_match(struct device *dev, void *res, void *match_data)
  */
 void pci_epc_put(struct pci_epc *epc)
 {
-	if (!epc || IS_ERR(epc))
+	if (IS_ERR_OR_NULL(epc))
 		return;
 
 	module_put(epc->ops->owner);
@@ -660,7 +660,7 @@ void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
 	struct list_head *list;
 	u32 func_no = 0;
 
-	if (!epc || IS_ERR(epc) || !epf)
+	if (IS_ERR_OR_NULL(epc) || !epf)
 		return;
 
 	if (type == PRIMARY_INTERFACE) {
@@ -691,7 +691,7 @@ void pci_epc_linkup(struct pci_epc *epc)
 {
 	struct pci_epf *epf;
 
-	if (!epc || IS_ERR(epc))
+	if (IS_ERR_OR_NULL(epc))
 		return;
 
 	mutex_lock(&epc->list_lock);
@@ -717,7 +717,7 @@ void pci_epc_linkdown(struct pci_epc *epc)
 {
 	struct pci_epf *epf;
 
-	if (!epc || IS_ERR(epc))
+	if (IS_ERR_OR_NULL(epc))
 		return;
 
 	mutex_lock(&epc->list_lock);
@@ -743,7 +743,7 @@ void pci_epc_init_notify(struct pci_epc *epc)
 {
 	struct pci_epf *epf;
 
-	if (!epc || IS_ERR(epc))
+	if (IS_ERR_OR_NULL(epc))
 		return;
 
 	mutex_lock(&epc->list_lock);
@@ -769,7 +769,7 @@ void pci_epc_bme_notify(struct pci_epc *epc)
 {
 	struct pci_epf *epf;
 
-	if (!epc || IS_ERR(epc))
+	if (IS_ERR_OR_NULL(epc))
 		return;
 
 	mutex_lock(&epc->list_lock);