Documentation/networking: Update Intel Wired LAN docs

- Update the Intel Wired LAN documentation with the latest
  URL for ethtool.

- replace "Ethtool" with "ethtool"

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Emil Tantilov <emil.s.tantilov@intel.com>
diff --git a/Documentation/networking/igb.txt b/Documentation/networking/igb.txt
index 4a5e29c..98953c0 100644
--- a/Documentation/networking/igb.txt
+++ b/Documentation/networking/igb.txt
@@ -62,15 +62,15 @@
   -------
   The driver utilizes the ethtool interface for driver configuration and
   diagnostics, as well as displaying statistical information. The latest
-  version of Ethtool can be found at:
+  version of ethtool can be found at:
 
   http://ftp.kernel.org/pub/software/network/ethtool/
 
   Enabling Wake on LAN* (WoL)
   ---------------------------
-  WoL is configured through the Ethtool* utility.
+  WoL is configured through the ethtool* utility.
 
-  For instructions on enabling WoL with Ethtool, refer to the Ethtool man page.
+  For instructions on enabling WoL with ethtool, refer to the ethtool man page.
 
   WoL will be enabled on the system during the next shut down or reboot.
   For this driver version, in order to enable WoL, the igb driver must be