target/i386/helper: Remove do_cpu_sipi() stub for user-mode emulation

Since commit  604664726f ("target/i386: Restrict cpu_exec_interrupt()
handler to sysemu"), do_cpu_sipi() isn't called anymore on user
emulation. Remove the now pointless stub.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230602224628.59546-2-philmd@linaro.org>
2 files changed