CI: Add clang-format checker

Signed-off-by: Andreas Fuchs <andreas.fuchs@infineon.com>

Author: AndreasFuchsTPM

.github/workflows/clang_format.yml

@@ -0,0 +1,11 @@
+name: Clang Format Checker
+on:
+  [push, pull_request]
+jobs:
+  clang-format-checking:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: RafikFarhad/clang-format-github-action@v3
+        with:
+          sources: "include/tss2/*.h,src/**/*.h,src/**/*.c,test/**/*.h,test/**/*.c"