chardev/char.c: Use qemu_co_sleep_ns if in coroutine

To be able to convert compare_chr_send to a coroutine in the
next commit, use qemu_co_sleep_ns if in coroutine.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
1 file changed