ci: clang: do not error if using deprecated function
I do not think that deprecation warnings from dependencies should break the CI build.
This adds the exception for this warnings type for C. It is already set for C++.
An example warning:
../src/amd/llvm/ac_llvm_build.c:321:11: warning: 'LLVMBuildCall' is deprecated: Use LLVMBuildCall2 instead to support opaque pointers [-Wdeprecated-declarations]
call = LLVMBuildCall(ctx->builder, function, params, param_count, "");
^
/usr/lib/llvm-14/include/llvm-c/Core.h:3990:1: note: 'LLVMBuildCall' has been explicitly marked deprecated here
LLVM_ATTRIBUTE_C_DEPRECATED(
^
/usr/lib/llvm-14/include/llvm-c/Deprecated.h:26:23: note: expanded from macro 'LLVM_ATTRIBUTE_C_DEPRECATED'
decl __attribute__((deprecated(message)))