net/ethtool: Fix program call.

I missed removing a call to the old ethtool function wrapper that was
made unneeded by commit d02d3af02.

X-Gentoo-Bug: 399037
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=399037
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

net/ethtool.sh

@@ -39,7 +39,7 @@ ethtool_pre_start() {
 			args_pretty="--${opt} $IFACE ${args_pretty}"
 			args="--${opt} $IFACE ${args}"
 			ebegin "ethtool ${args_pretty}"
-			$(_ethtool) ${args}
+			ethtool ${args}
 			rc=$?
 			eend $rc "ethtool exit code $rc"
 			# TODO: ethtool has MANY different exit codes, with no