Trivial typo fix in variadic

Trivial typo fix in variadic

Fix all occurences of varadic, except for Rust (will be part of another change).

gcc/ChangeLog:

	* config/nvptx/nvptx.h (struct machine_function): Fix typo in variadic.
	* config/nvptx/nvptx.cc (nvptx_function_arg_advance): Adjust to use fixed name.
	(nvptx_declare_function_name): Likewise.
	(nvptx_call_args): Likewise.
	(nvptx_expand_call): Likewise.

gcc/cp/ChangeLog:

	* lambda.cc (compare_lambda_sig): Fix typo in variadic.

libcpp/ChangeLog:

	* macro.cc (parse_params): Fix typo in variadic.
	(create_iso_definition): Likewise.

Signed-off-by: Marc Poulhiès <dkm@kataplop.net>