tg3: fix return value check in tg3_read_vpd()

Besides -ETIMEDOUT and -EINTR, pci_read_vpd may return other error
values like -ENODEV or -EINVAL which are ignored due to the buggy
check, but the data are not read from VPD anyway and this is checked
subsequently with at most 3 needless loop iterations. This does not
show up as a runtime bug.

CC: Matt Carlson <mcarlson@broadcom.com>
CC: Michael Chan <mchan@broadcom.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -12658,7 +12658,7 @@ static void __devinit tg3_read_vpd(struct tg3 *tp)
 			cnt = pci_read_vpd(tp->pdev, pos,
 					   TG3_NVM_VPD_LEN - pos,
 					   &vpd_data[pos]);
-			if (cnt == -ETIMEDOUT || -EINTR)
+			if (cnt == -ETIMEDOUT || cnt == -EINTR)
 				cnt = 0;
 			else if (cnt < 0)
 				goto out_not_found;