boot/edk2: fix legal-info

Fix typo: EDK2_LICENSE_FILE -> EDK2_LICENSE_FILES
added by commit 1074a37e783b023bd0491ba4f4f7acab7f289e1d

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 889a7917b170f9e9c1bb32b3601824c313354d77)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/edk2/edk2.mk

@@ -8,7 +8,7 @@ EDK2_VERSION = edk2-stable202102
 EDK2_SITE = https://github.com/tianocore/edk2
 EDK2_SITE_METHOD = git
 EDK2_LICENSE = BSD-2-Clause
-EDK2_LICENSE_FILE = License.txt
+EDK2_LICENSE_FILES = License.txt
 EDK2_CPE_ID_VENDOR = tianocore
 EDK2_DEPENDENCIES = edk2-platforms host-python3 host-acpica host-util-linux
 EDK2_INSTALL_TARGET = NO