block: Add including of ioctl header for Emscripten build

block: Add including of ioctl header for Emscripten build

Including <sys/ioctl.h> is still required on Emscripten, just like on other
platforms, to make the ioctl function available.

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/49b6ecdbd23ff83e3f191ef8a9f7cc2feeaea43f.1745820062.git.ktokunaga.mail@gmail.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>