ixgbe: fix SFF data dumps of SFP+ modules from an offset

This patch fixes the read loop for the I2C data to account for the offset.

Also includes a whitespace cleanup and removes ret_val as it is not needed.

CC: Ben Hutchings <bhutchings@solarflare.com>
Reported-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c

@@ -2946,12 +2946,11 @@ static int ixgbe_get_module_eeprom(struct net_device *dev,
 	u32 status = IXGBE_ERR_PHY_ADDR_INVALID;
 	u8 databyte = 0xFF;
 	int i = 0;
-	int ret_val = 0;
 
 	if (ee->len == 0)
 		return -EINVAL;
 
-	for (i = ee->offset; i < ee->len; i++) {
+	for (i = ee->offset; i < ee->offset + ee->len; i++) {
 		/* I2C reads can take long time */
 		if (test_bit(__IXGBE_IN_SFP_INIT, &adapter->state))
 			return -EBUSY;
@@ -2962,12 +2961,12 @@ static int ixgbe_get_module_eeprom(struct net_device *dev,
 			status = hw->phy.ops.read_i2c_sff8472(hw, i, &databyte);
 
 		if (status != 0)
-			ret_val = -EIO;
+			return -EIO;
 
 		data[i - ee->offset] = databyte;
 	}
 
-	return ret_val;
+	return 0;
 }
 
 static const struct ethtool_ops ixgbe_ethtool_ops = {