boot/arm-trusted-firmware: point LICENSE_FILES to correct file

Since v2.2 release (commits 8cc36aec912 "doc: De-duplicate readme and
license files" and 9f1622b018ab "doc: Move content out of readme and
create new index page "), the license.rst file at the root of the git
repo is only telling to look at docs/license.rst file.

Let's point the ARM_TRUSTED_FIRMWARE_LICENSE_FILES to the correct file
and modify the .hash file accordingly.

The comment has also been wrong since we bumped from version 1.4 to 2.2
in commit  a757d173f179  (boot/arm-trusted-firmware: bump to version
2.2). Drop referencing an explicit version, so that is is never wrong
again.

Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
[yann.morin.1998@free.fr: also fix the comment.]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 83541769159ed7a8241cf82ab56db56e5c96a126)
[Peter: update hash for v2.4]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/arm-trusted-firmware/arm-trusted-firmware.hash

@@ -1,3 +1,3 @@
 # Locally calculated
 sha256  4bfda9fdbe5022f2e88ad3344165f7d38a8ae4a0e2d91d44d9a1603425cc642d  arm-trusted-firmware-v2.4.tar.gz
-sha256  487795b8023df866259fa159bab94706b747fb0d623b7913f1c4955c0ab5f164  license.rst
+sha256  13676fa9170d3e6da3f7562d2d47b8b71090b1b45013fbd329ef847841f3a0b1  docs/license.rst

boot/arm-trusted-firmware/arm-trusted-firmware.mk

@@ -18,10 +18,10 @@ else
 # Handle stable official ATF versions
 ARM_TRUSTED_FIRMWARE_SITE = $(call github,ARM-software,arm-trusted-firmware,$(ARM_TRUSTED_FIRMWARE_VERSION))
 # The licensing of custom or from-git versions is unknown.
-# This is valid only for the official v1.4.
+# This is valid only for the latest (i.e. known) version.
 ifeq ($(BR2_TARGET_ARM_TRUSTED_FIRMWARE_LATEST_VERSION),y)
 ARM_TRUSTED_FIRMWARE_LICENSE = BSD-3-Clause
-ARM_TRUSTED_FIRMWARE_LICENSE_FILES = license.rst
+ARM_TRUSTED_FIRMWARE_LICENSE_FILES = docs/license.rst
 endif
 endif