staging: comedi: addi_apci_3120: use async->events to report hardware error

In apci3120_interrupt_dma(), use the async->events to report the hardware
error and allow the core to (*cancel) the command instead of calling the
(*cancel) function directly.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>