ethtool: Update to 4.15.

Contains kernel 4.14 updates. Compile tested on mvebu.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

package/network/utils/ethtool/Makefile

@@ -8,13 +8,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ethtool
-PKG_VERSION:=4.13
+PKG_VERSION:=4.15
 PKG_RELEASE:=1
 
 PKG_MAINTAINER:=Felix Fietkau <nbd@nbd.name>
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/software/network/ethtool
-PKG_HASH:=b7c1a380007d30eaf261a63b3cfc000f9d93f9eb7626dcd48b5d2a733af99cba
+PKG_HASH:=71f7fd32483ffdc7c6c4d882e230714eb101df0a46cbe396dbeb8ac78f1ef91a
 
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=COPYING