staging: comedi: me4000: remove 'chan' check in me4000_ai_insn_read()

The comedi core validates that the 'chan' is valid for the subdevice
before calling the (*insn_read) operation. Remove the unnecessary check.
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/me4000.c

@@ -477,11 +477,6 @@ static int me4000_ai_insn_read(struct comedi_device *dev,
 	switch (aref) {
 	case AREF_GROUND:
 	case AREF_COMMON:
-		if (chan >= board->ai_nchan) {
-			dev_err(dev->class_dev,
-				"Analog input is not available\n");
-			return -EINVAL;
-		}
 		entry |= ME4000_AI_LIST_INPUT_SINGLE_ENDED | chan;
 		break;