linux-user: Disable more prctl subcodes

linux-user: Disable more prctl subcodes

Create a list of subcodes that we want to pass on, a list of
subcodes that should not be passed on because they would affect
the running qemu itself, and a list that probably could be
implemented but require extra work. Do not pass on unknown subcodes.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211227150127.2659293-3-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>