ethtool: update to 3.18

This release contains a patch which is supposed to improve musl compatiblity. I
haven't tested it with musl though.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

net/ethtool/Makefile

@@ -8,13 +8,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ethtool
-PKG_VERSION:=3.15
+PKG_VERSION:=3.18
 PKG_RELEASE:=1
 
 PKG_MAINTAINER:=Matthias Schiffer <mschiffer@universe-factory.net>
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/software/network/ethtool
-PKG_MD5SUM:=e7bf0c355d2bf6ee281ebc713c5fb987
+PKG_MD5SUM:=fbf1a167b88a5966a2c56a2483af68c6
 
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=COPYING