Revert "avrdude: add license information"

This reverts commit d1f545004bf0533064363d87c2d7c71e7acf7435 from 2014
because the added variables already existed. The real problem at the
time was that one of the pre-existent variables had a typo, fixed in a
later commit.

Currently AVRDUDE_LICENSE and AVRDUDE_LICENSE_FILES are declared twice
with the same values for each one. So remove one of them.

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Cc: Wojciech M. Zabolotny <wzab01@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit d6bce837ec80b65a873e6c12ae1f813ed505e006)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/avrdude/avrdude.mk

@@ -15,8 +15,6 @@ AVRDUDE_AUTORECONF = YES
 AVRDUDE_CONF_OPTS = --enable-linuxgpio
 AVRDUDE_DEPENDENCIES = elfutils libusb libusb-compat ncurses \
 	host-flex host-bison
-AVRDUDE_LICENSE = GPL-2.0+
-AVRDUDE_LICENSE_FILES = avrdude/COPYING
 
 ifeq ($(BR2_PACKAGE_LIBFTDI1),y)
 AVRDUDE_DEPENDENCIES += libftdi1