libusb: define license

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libusb/libusb.mk

@@ -6,6 +6,8 @@
 LIBUSB_VERSION = 1.0.9
 LIBUSB_SOURCE = libusb-$(LIBUSB_VERSION).tar.bz2
 LIBUSB_SITE = http://$(BR2_SOURCEFORGE_MIRROR).dl.sourceforge.net/project/libusb/libusb-1.0/libusb-$(LIBUSB_VERSION)
+LIBUSB_LICENSE = LGPLv2.1+
+LIBUSB_LICENSE_FILES = COPYING
 LIBUSB_DEPENDENCIES = host-pkg-config
 LIBUSB_INSTALL_STAGING = YES