staging: comedi: ni_mio_common: ack ai fifo error interrupts.

Ack ai fifo error interrupts in interrupt handler to clear interrupt
after fifo overflow.  It should prevent lock-ups after the ai fifo
overflows.

Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Frank Mori Hess <fmh6jj@gmail.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_mio_common.c

@@ -1275,6 +1275,8 @@ static void ack_a_interrupt(struct comedi_device *dev, unsigned short a_status)
 		ack |= NISTC_INTA_ACK_AI_START;
 	if (a_status & NISTC_AI_STATUS1_STOP)
 		ack |= NISTC_INTA_ACK_AI_STOP;
+	if (a_status & NISTC_AI_STATUS1_OVER)
+		ack |= NISTC_INTA_ACK_AI_ERR;
 	if (ack)
 		ni_stc_writew(dev, ack, NISTC_INTA_ACK_REG);
 }