Generate an ioctl request code for a command that passes no data.
This is equivalent to the
_IO() macro exposed by the C ioctl API.
You should only use this macro directly if the
ioctl you're working
with is "bad" and you cannot use
const KVMIO: u8 = 0xAE; ioctl_write_int_bad!(kvm_create_vm, request_code_none!(KVMIO, 0x03));