ntb: epf: 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>

drivers/ntb/hw/epf/ntb_hw_epf.c

@@ -617,14 +617,11 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 	ndev->db_reg = pci_iomap(pdev, ndev->db_reg_bar, 0);
 	if (!ndev->db_reg) {
 		ret = -EIO;
-		goto err_dma_mask;
+		goto err_pci_regions;
 	}
 
 	return 0;
 
-err_dma_mask:
-	pci_clear_master(pdev);
-
 err_pci_regions:
 	pci_disable_device(pdev);
 
@@ -642,7 +639,6 @@ static void ntb_epf_deinit_pci(struct ntb_epf_dev *ndev)
 	pci_iounmap(pdev, ndev->peer_spad_reg);
 	pci_iounmap(pdev, ndev->db_reg);
 
-	pci_clear_master(pdev);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 	pci_set_drvdata(pdev, NULL);