Add clang-format style for project

This adds a .clang-format file for the project.
Requires clang-format-17:
docker run -u 1000 -v $PWD:$PWD xianpengshen/clang-tools:17 \
clang-format -i $(find -name '*.c' | xargs realpath)

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

Author: AndreasFuchsTPM

.clang-format

@@ -0,0 +1,29 @@
+# SPDX-FileCopyrightText: Copyright (c) 2023-2024 Infineon Technologies AG
+#
+# SPDX-License-Identifier: BSD-2-clause
+
+---
+
+BasedOnStyle: GNU
+
+IndentWidth: 4
+ColumnLimit: 100
+
+BreakBeforeBraces: Attach
+
+AlignAfterOpenBracket: Align
+AlignConsecutiveDeclarations: true
+BinPackParameters: false
+AllowAllParametersOfDeclarationOnNextLine: false
+
+SpaceBeforeParens: ControlStatementsExceptControlMacros
+AlignConsecutiveMacros:
+  Enabled: true
+  AcrossEmptyLines: true
+  AcrossComments: false
+
+Macros:
+- statecase(VAR, STATE)=case 0:{}
+- general_failure(VAR)=default:{}
+- statecasedefault(VAR)=default:{}
+- statecasedefault_error(VAR, r, label)=default:{}

.git-blame-ignore-revs

@@ -0,0 +1 @@
+# .git-blame-ignore-revs

doc/coding_standard_c.md

@@ -5,6 +5,15 @@ notably is the indentation (more on this later). Above all else we ask
 that when modifying the code that you follow the most important rule:
 check the surrounding code and imitate its style [1].
 
+## Clang-Format Style
+For simplicity, we use clang-format for all files (also as part of the CI).
+Thus before commiting any code, we recommend you run
+```sh
+docker run -u 1000 -v $PWD:$PWD xianpengshen/clang-tools:17 clang-format -i $(find -name '*.c' | xargs realpath)
+docker run -u 1000 -v $PWD:$PWD xianpengshen/clang-tools:17 clang-format -i $(find -name '*.h' | xargs realpath)
+```
+This ensures that the code will not break during your pull request.
+
 ## C Standard and Compiler Stuff
 Code should hold as close to the C99 standard as possible with the exception
 that GCC specific extensions are generally accepted. The code must compile