fw: Import tkey-libs fw-2

This is an import of the fw-2 tag of tkey-libs.

We import the entire tkey-libs repo minus dot files into the
tillitis-key1 repo to make it very simple not to make mistakes
regarding which firmware tag depends on which tkey-libs tag,
especially considering locking down with NVCM.

Please see README for information about developing with another
tkey-libs or how to import future tkey-libs.

Since tkey-libs is now a part of the repo we also add tkey-libs to the
clean_fw target.

hw/application_fpga/tkey-libs/tools/spdx-ensure

@@ -0,0 +1,92 @@
+#!/bin/bash
+# SPDX-FileCopyrightText: 2022 Tillitis AB <tillitis.se>
+# SPDX-License-Identifier: BSD-2-Clause
+set -eu
+
+# Check for the SPDX tag in all files in the repo. Exit with a non-zero code if
+# some is missing. The missingok arrays below contain files and directories
+# with files where the the tag is not required.
+
+cd "${0%/*}"
+cd ..
+
+tag="SPDX-License-Identifier:"
+
+missingok_dirs=(
+.github/workflows/
+LICENSES/
+)
+
+missingok_files=(
+.clang-format
+.editorconfig
+.gitignore
+LICENSE
+Makefile
+README.md
+README-DIST.txt
+RELEASE.md
+example-app/Makefile
+monocypher/LICENSE
+monocypher/README.md
+)
+
+is_missingok() {
+  item="$1"
+  # ok for empty files
+  [[ -f "$item" ]] && [[ ! -s "$item" ]] && return 0
+  for fileok in "${missingok_files[@]}"; do
+    [[ "$item" = "$fileok" ]] && return 0
+  done
+  for dirok in "${missingok_dirs[@]}"; do
+    [[ "$item" =~ ^$dirok ]] && return 0
+  done
+  return 1
+}
+
+printf "* Checking for SPDX tags in %s\n" "$PWD"
+
+mapfile -t repofiles < <(git ls-files || true)
+if [[ -z "${repofiles[*]}" ]]; then
+  printf "* No files in the repo?!\n"
+  exit 1
+fi
+
+failed=0
+
+printed=0
+for fileok in "${missingok_files[@]}"; do
+  [[ -f "$fileok" ]] && continue
+  if (( !printed )); then
+    printf "* Some files in missingok_files are themselves missing:\n"
+    printed=1
+    failed=1
+  fi
+  printf "%s\n" "$fileok"
+done
+
+printed=0
+for dirok in "${missingok_dirs[@]}"; do
+  [[ -d "$dirok" ]] && continue
+  if (( !printed )); then
+    printf "* Some dirs in missingok_dirs are themselves missing:\n"
+    printed=1
+    failed=1
+  fi
+  printf "%s\n" "$dirok"
+done
+
+printed=0
+for file in "${repofiles[@]}"; do
+  is_missingok "$file" && continue
+  if ! grep -q "$tag" "$file"; then
+    if (( !printed )); then
+      printf "* Files missing the SPDX tag:\n"
+      printed=1
+      failed=1
+    fi
+    printf "%s\n" "$file"
+  fi
+done
+
+exit "$failed"