staging: comedi: ni_mio_common: remove some unnecessary BUG_ON()

The mite dma channels are only requested by a subdevice with a (*do_cmd)
and they are released by a (*cancel). The comedi core will only call the
(*do_cmd) if the subdevice is not already running a command and all
commands are terminated by the core with a (*cancel).

Remove the BUG_ON() checks in the request functions which can never
happen.
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>

drivers/staging/comedi/drivers/ni_mio_common.c

@@ -665,7 +665,6 @@ static int ni_request_ai_mite_channel(struct comedi_device *dev)
 	unsigned long flags;
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
-	BUG_ON(devpriv->ai_mite_chan);
 	devpriv->ai_mite_chan =
 	    mite_request_channel(devpriv->mite, devpriv->ai_mite_ring);
 	if (!devpriv->ai_mite_chan) {
@@ -686,7 +685,6 @@ static int ni_request_ao_mite_channel(struct comedi_device *dev)
 	unsigned long flags;
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
-	BUG_ON(devpriv->ao_mite_chan);
 	devpriv->ao_mite_chan =
 	    mite_request_channel(devpriv->mite, devpriv->ao_mite_ring);
 	if (!devpriv->ao_mite_chan) {
@@ -710,7 +708,6 @@ static int ni_request_gpct_mite_channel(struct comedi_device *dev,
 	struct mite_channel *mite_chan;
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
-	BUG_ON(devpriv->counter_dev->counters[gpct_index].mite_chan);
 	mite_chan =
 	    mite_request_channel(devpriv->mite,
 				 devpriv->gpct_mite_ring[gpct_index]);
@@ -737,7 +734,6 @@ static int ni_request_cdo_mite_channel(struct comedi_device *dev)
 	unsigned long flags;
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
-	BUG_ON(devpriv->cdo_mite_chan);
 	devpriv->cdo_mite_chan =
 	    mite_request_channel(devpriv->mite, devpriv->cdo_mite_ring);
 	if (!devpriv->cdo_mite_chan) {