ethtool: bump version, use new upstream location

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/ethtool/ethtool.mk

@@ -4,7 +4,7 @@
 #
 #############################################################
 
-ETHTOOL_VERSION = 2.6.35
-ETHTOOL_SITE = http://$(BR2_SOURCEFORGE_MIRROR).dl.sourceforge.net/sourceforge/gkernel/
+ETHTOOL_VERSION = 2.6.38
+ETHTOOL_SITE = $(BR2_KERNEL_MIRROR)/software/network/ethtool/
 
 $(eval $(call AUTOTARGETS,package,ethtool))