staging: comedi: me4000: Fix endian problem for AI command data

commit b39dfcc upstream.

The analog input subdevice supports Comedi asynchronous commands that
use Comedi's 16-bit sample format.  However, the calls to
`comedi_buf_write_samples()` are passing the address of a 32-bit integer
variable.  On bigendian machines, this will copy 2 bytes from the wrong
end of the 32-bit value.  Fix it by changing the type of the variable
holding the sample value to `unsigned short`.

Fixes: de88924 ("staging: comedi: me4000: use comedi_buf_write_samples()")
Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-8-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/me4000.c

@@ -924,7 +924,7 @@ static irqreturn_t me4000_ai_isr(int irq, void *dev_id)
 	struct comedi_subdevice *s = dev->read_subdev;
 	int i;
 	int c = 0;
-	unsigned int lval;
+	unsigned short lval;
 
 	if (!dev->attached)
 		return IRQ_NONE;