target/i386: Remove user-only i/o stubs

With the previous patch for check_io, we now have enough for
the compiler to dead-code eliminate all of the i/o helpers.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210514151342.384376-51-richard.henderson@linaro.org>
4 files changed