firewire: ohci: use devres for MMIO region mapping

The PCI framework has the convenient helper function to check and map MMIO
region with managed device resource.

This commit elaborates 1394 OHCI driver to use the function.

Link: https://lore.kernel.org/r/20230604054451.161076-4-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

drivers/firewire/ohci.c

@@ -3608,18 +3608,12 @@ static int pci_probe(struct pci_dev *dev,
 		return -ENXIO;
 	}
 
-	err = pci_request_region(dev, 0, ohci_driver_name);
+	err = pcim_iomap_regions(dev, 1 << 0, ohci_driver_name);
 	if (err) {
-		ohci_err(ohci, "MMIO resource unavailable\n");
-		return err;
-	}
-
-	ohci->registers = pci_iomap(dev, 0, OHCI1394_REGISTER_SIZE);
-	if (ohci->registers == NULL) {
-		ohci_err(ohci, "failed to remap registers\n");
-		err = -ENXIO;
-		goto fail_iomem;
+		ohci_err(ohci, "request and map MMIO resource unavailable\n");
+		return -ENXIO;
 	}
+	ohci->registers = pcim_iomap_table(dev)[0];
 
 	for (i = 0; i < ARRAY_SIZE(ohci_quirks); i++)
 		if ((ohci_quirks[i].vendor == dev->vendor) &&
@@ -3644,10 +3638,8 @@ static int pci_probe(struct pci_dev *dev,
 					       PAGE_SIZE,
 					       &ohci->misc_buffer_bus,
 					       GFP_KERNEL);
-	if (!ohci->misc_buffer) {
-		err = -ENOMEM;
-		goto fail_iounmap;
-	}
+	if (!ohci->misc_buffer)
+		return -ENOMEM;
 
 	err = ar_context_init(&ohci->ar_request_ctx, ohci, 0,
 			      OHCI1394_AsReqRcvContextControlSet);
@@ -3747,10 +3739,6 @@ static int pci_probe(struct pci_dev *dev,
  fail_misc_buf:
 	dma_free_coherent(ohci->card.device, PAGE_SIZE,
 			  ohci->misc_buffer, ohci->misc_buffer_bus);
- fail_iounmap:
-	pci_iounmap(dev, ohci->registers);
- fail_iomem:
-	pci_release_region(dev, 0);
 
 	return err;
 }
@@ -3793,8 +3781,6 @@ static void pci_remove(struct pci_dev *dev)
 	kfree(ohci->it_context_list);
 	kfree(ohci->ir_context_list);
 	pci_disable_msi(dev);
-	pci_iounmap(dev, ohci->registers);
-	pci_release_region(dev, 0);
 
 	dev_notice(&dev->dev, "removing fw-ohci device\n");
 }