IB/ipath: Use pci_dev->revision, again

Commit 44c10138 ("PCI: Change all drivers to use pci_device->revision")
already converted this driver to using the revision field of struct
pci_dev but commit bb917144 ("IB/ipath: Misc changes to prepare
for IB7220 introduction") later reverted that change for some strange
reason.  Restore the change.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/ipath/ipath_driver.c

@@ -398,7 +398,6 @@ static int __devinit ipath_init_one(struct pci_dev *pdev,
 	struct ipath_devdata *dd;
 	unsigned long long addr;
 	u32 bar0 = 0, bar1 = 0;
-	u8 rev;
 
 	dd = ipath_alloc_devdata(pdev);
 	if (IS_ERR(dd)) {
@@ -540,13 +539,7 @@ static int __devinit ipath_init_one(struct pci_dev *pdev,
 		goto bail_regions;
 	}
 
-	ret = pci_read_config_byte(pdev, PCI_REVISION_ID, &rev);
-	if (ret) {
-		ipath_dev_err(dd, "Failed to read PCI revision ID unit "
-			      "%u: err %d\n", dd->ipath_unit, -ret);
-		goto bail_regions;	/* shouldn't ever happen */
-	}
-	dd->ipath_pcirev = rev;
+	dd->ipath_pcirev = pdev->revision;
 
 #if defined(__powerpc__)
 	/* There isn't a generic way to specify writethrough mappings */