rt2x00: rt2800: convert read_eeprom functions to return an int value

Both the rtt2x00usb_eeprom_read and the ioremap
functions are allowed to fail, however their
return values are not checked in the read_eeprom
functions in the rt2800{pci,usb} drivers.

The patch adds the missing checks, and converts
all read_eeprom functions to return an int value,
so the error values can be propagated up to the
'rt2800_validate_eeprom' function.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2800usb.c b/drivers/net/wireless/rt2x00/rt2800usb.c
index 5c149b5..4721cad 100644
--- a/drivers/net/wireless/rt2x00/rt2800usb.c
+++ b/drivers/net/wireless/rt2x00/rt2800usb.c
@@ -735,13 +735,17 @@
 /*
  * Device probe functions.
  */
-static void rt2800usb_read_eeprom(struct rt2x00_dev *rt2x00dev)
+static int rt2800usb_read_eeprom(struct rt2x00_dev *rt2x00dev)
 {
+	int retval;
+
 	if (rt2800_efuse_detect(rt2x00dev))
-		rt2800_read_eeprom_efuse(rt2x00dev);
+		retval = rt2800_read_eeprom_efuse(rt2x00dev);
 	else
-		rt2x00usb_eeprom_read(rt2x00dev, rt2x00dev->eeprom,
-				      EEPROM_SIZE);
+		retval = rt2x00usb_eeprom_read(rt2x00dev, rt2x00dev->eeprom,
+					       EEPROM_SIZE);
+
+	return retval;
 }
 
 static int rt2800usb_probe_hw(struct rt2x00_dev *rt2x00dev)