feat(dice): add typedefs from the Open DICE repo

The DPE implementation in RSS is aligned with the
Open Profile for DICE specification:
https://pigweed.googlesource.com/open-dice/

Type definitions are needed to specify the input
values for the DPE service. Instead of mandating to
clone the entire open-dice repo, the following file
is copied from the repository:
https://pigweed.googlesource.com/open-dice/+/refs/heads/main/include/dice/dice.h
Git SHA of the source version: cf549422e39da872d64993be944099ac62ba22a9

This is external code, with Apache 2.0 license, therefore
the license.rst is updated accordingly and a copy of this
license is also added.

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Signed-off-by: David Vincze <david.vincze@arm.com>
Change-Id: Ie84b8483034819d1143fe0ec812e66514ac7d4cb
diff --git a/docs/license.rst b/docs/license.rst
index 80f1118..8996105 100644
--- a/docs/license.rst
+++ b/docs/license.rst
@@ -85,6 +85,17 @@
 
    See the original `Linux MIT license`_.
 
+-  Some source files originating from the `Open Profile for DICE`_ project.
+   These files are licensed under the Apache License, Version 2.0, which is a
+   permissive license compatible with BSD-3-Clause. Any contributions to this
+   code must also be made under the terms of `Apache License 2.0`_.
+   These files are:
+
+   -  ``include/lib/dice/dice.h``
+
 .. _FreeBSD: http://www.freebsd.org
 .. _Linux MIT license: https://raw.githubusercontent.com/torvalds/linux/master/LICENSES/preferred/MIT
 .. _SCC: http://www.simple-cc.org/
+.. _Open Profile for DICE: https://pigweed.googlesource.com/open-dice/
+.. _Apache License 2.0: https://www.apache.org/licenses/LICENSE-2.0.txt
+