Rename to do_tr_or_bp, as per the kernel function.
Add a 'trap' argument, akin to the kernel's si_code, but clearer.
The return value is always 0, so change the return value to void.
Use force_sig and force_sig_fault.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220107213243.212806-15-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>