staging: comedi: use unsigned sample in cfc_write_to_buffer()

Sample values in comedi are generally represented as unsigned values.
`cfc_write_to_buffer()` in "comedi_fc.h" currently uses `short` to hold
a 16-bit sample value to be written to the buffer.  Change the type of
the parameter to `unsigned short` for consistency.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/comedi_fc.h

@@ -30,7 +30,7 @@ extern unsigned int cfc_write_array_to_buffer(struct comedi_subdevice *subd,
 					      unsigned int num_bytes);
 
 static inline unsigned int cfc_write_to_buffer(struct comedi_subdevice *subd,
-					       short data)
+					       unsigned short data)
 {
 	return cfc_write_array_to_buffer(subd, &data, sizeof(data));
 };