[BUG] opencl-interop `get_device_type` always returns `DeviceType::ALL`

[nikhilr612]

Description

The get_device_type function transmutes the value -1 into DeviceType or returns DeviceType::ALL; however, the enum variant that corresponds to the value (-1i32 as u64) is DeviceType::ALL. This does not seem to be the intended behaviour.

///// Fetch Active ArrayFire device's type i.e. CPU/GPU/Accelerator etc.
pub fn get_device_type() -> DeviceType {
    let mut out: i32 = 0;
    let err_val = unsafe { afcl_get_device_type(&mut out as *mut c_int) };
    handle_error_general(AfError::from(err_val));
    match out {
        -1 => unsafe { mem::transmute(out as u64) },
        _ => DeviceType::ALL,
    }
}

The value of -1 corresponds to AFCL_DEVICE_TYPE_UNKNOWN in arrayfire, whilst -1 corresponds to CL_DEVICE_TYPE_ALL in cl-sys