staging: comedi: dt2801: change function return type to void

cppcheck was complaining that the variable 'stat' is being reassigned
before the old value is used.  Upon inspection, I found that
dt2801_writecmd() cannot fail, always returns 0, and most callers already
do not bother with assigning its return value anyway, so it makes sense to
just change the return type for this function from int to void, and remove
the two assignments to 'stat'.
Signed-off-by: Chase Southwood <chase.southwood@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/dt2801.c

@@ -309,7 +309,7 @@ static int dt2801_wait_for_ready(struct comedi_device *dev)
 	return -ETIME;
 }
 
-static int dt2801_writecmd(struct comedi_device *dev, int command)
+static void dt2801_writecmd(struct comedi_device *dev, int command)
 {
 	int stat;
 
@@ -323,8 +323,6 @@ static int dt2801_writecmd(struct comedi_device *dev, int command)
 	if (!(stat & DT_S_READY))
 		dev_dbg(dev->class_dev, "!ready in %s, ignoring\n", __func__);
 	outb_p(command, dev->iobase + DT2801_CMD);
-
-	return 0;
 }
 
 static int dt2801_reset(struct comedi_device *dev)
@@ -380,7 +378,7 @@ static int probe_number_of_ai_chans(struct comedi_device *dev)
 	int data;
 
 	for (n_chans = 0; n_chans < 16; n_chans++) {
-		stat = dt2801_writecmd(dev, DT_C_READ_ADIM);
+		dt2801_writecmd(dev, DT_C_READ_ADIM);
 		dt2801_writedata(dev, 0);
 		dt2801_writedata(dev, n_chans);
 		stat = dt2801_readdata2(dev, &data);
@@ -451,7 +449,7 @@ static int dt2801_ai_insn_read(struct comedi_device *dev,
 	int i;
 
 	for (i = 0; i < insn->n; i++) {
-		stat = dt2801_writecmd(dev, DT_C_READ_ADIM);
+		dt2801_writecmd(dev, DT_C_READ_ADIM);
 		dt2801_writedata(dev, CR_RANGE(insn->chanspec));
 		dt2801_writedata(dev, CR_CHAN(insn->chanspec));
 		stat = dt2801_readdata2(dev, &d);