helper/list: Replace Linux code with FreeBSD one

helper/list: Replace Linux code with FreeBSD one

The file list.h was originally taken from the Linux kernel code,
thus under license GPL-2.0-only. This locks OpenOCD to follow the
same license, even if the majority of OpenOCD files are licensed
as GPL-2.0-or-later.

A similar file is also present in FreeBSD code base under the more
permissive license BSD-2-Clause.

Drop the code from Linux kernel and replace it with the code from
FreeBSD 13.3.0.
Adapt the code to OpenOCD coding style by fixing the majority of
issues identified by checkpatch.
Add the OpenOCD specific macros and comments.

Unfortunately this causes the lost of all the doxygen comments.

Checkpatch-ignore: MACRO_ARG_REUSE, MACRO_ARG_PRECEDENCE
Change-Id: I6d86752c50158f3174c4e8c4add81e9998d01e0e
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8172
Tested-by: jenkins