Clang format: Remove CPP language specifier

clang-format 20.1.0 adds C as a language instead of treating it as C++.
This breaks our clang-format configuration, which scopes the
configuration to CPP at the start of the config file, making the lint
action claim that C isn't supported by the configuration.

Signed-off-by: Trond Snekvik <trond@golioth.io>

Author: trond-snekvik

.clang-format

@@ -7,8 +7,6 @@
 #
 ---
 DisableFormat: false
-Language: Cpp
-Standard: Cpp11
 
 # Indentation & whitespace
 AccessModifierOffset: -4