net/ism: Remove redundant pci_clear_master

Remove pci_clear_master to simplify the code,
the bus-mastering is also cleared in do_pci_disable_device,
like this:
./drivers/pci/pci.c:2197
static void do_pci_disable_device(struct pci_dev *dev)
{
	u16 pci_command;

	pci_read_config_word(dev, PCI_COMMAND, &pci_command);
	if (pci_command & PCI_COMMAND_MASTER) {
		pci_command &= ~PCI_COMMAND_MASTER;
		pci_write_config_word(dev, PCI_COMMAND, pci_command);
	}

	pcibios_disable_device(dev);
}.
And dev->is_busmaster is set to 0 in pci_disable_device.
Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/ism_drv.c

@@ -675,7 +675,6 @@ static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	return 0;
 
 err_resource:
-	pci_clear_master(pdev);
 	pci_release_mem_regions(pdev);
 err_disable:
 	pci_disable_device(pdev);
@@ -738,7 +737,6 @@ static void ism_remove(struct pci_dev *pdev)
 	ism_dev_exit(ism);
 	mutex_unlock(&ism_dev_list.mutex);
 
-	pci_clear_master(pdev);
 	pci_release_mem_regions(pdev);
 	pci_disable_device(pdev);
 	device_del(&ism->dev);