kexec-lite: add KEXEC_LITE_LICENSE_FILES

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/kexec-lite/kexec-lite.mk

@@ -7,6 +7,7 @@
 KEXEC_LITE_VERSION = 86e45a47e8cc1f598ccfa9b873a23067f4ecc36f
 KEXEC_LITE_SITE = $(call github,antonblanchard,kexec-lite,$(KEXEC_LITE_VERSION))
 KEXEC_LITE_LICENSE = GPLv2+
+KEXEC_LITE_LICENSE_FILES = COPYING
 KEXEC_LITE_DEPENDENCIES = elfutils dtc
 
 define KEXEC_LITE_BUILD_CMDS