uboot-tools: fix license issues

Fix license directory and filename change, fixes:
http://autobuild.buildroot.net/results/8c9/8c94c81fe74399c854de335329cf4942f8356fbe/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/uboot-tools/uboot-tools.mk

@@ -8,7 +8,7 @@ UBOOT_TOOLS_VERSION = 2013.10
 UBOOT_TOOLS_SOURCE  = u-boot-$(UBOOT_TOOLS_VERSION).tar.bz2
 UBOOT_TOOLS_SITE    = ftp://ftp.denx.de/pub/u-boot
 UBOOT_TOOLS_LICENSE = GPLv2+
-UBOOT_TOOLS_LICENSE_FILES = COPYING
+UBOOT_TOOLS_LICENSE_FILES = Licenses/gpl-2.0.txt
 
 define UBOOT_TOOLS_BUILD_CMDS
 	$(MAKE) -C $(@D) 			\