package/libidn2: get rid of remnants of using := in LICENSE

There is no longer any reason to assign to LICENSE using an
immediate assignment. There was even no reason to use it
either in the first assignment.

Drop it.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/libidn2/libidn2.mk

@@ -6,7 +6,7 @@
 
 LIBIDN2_VERSION = 2.2.0
 LIBIDN2_SITE = $(BR2_GNU_MIRROR)/libidn
-LIBIDN2_LICENSE := GPL-2.0+ or LGPL-3.0+ (library)
+LIBIDN2_LICENSE = GPL-2.0+ or LGPL-3.0+ (library)
 LIBIDN2_LICENSE_FILES = COPYING COPYINGv2 COPYING.LESSERv3 COPYING.unicode
 LIBIDN2_DEPENDENCIES = \
 	host-pkgconf \