iio: adc: ad4130: Fix spelling mistake "diffreential" -> "differential"

There is a spelling mistake in an error message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20221104093148.167765-1-colin.i.king@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad4130.c

@@ -1480,7 +1480,7 @@ static int ad4130_validate_diff_channel(struct ad4130_state *st, u32 pin)
 
 	if (pin >= AD4130_MAX_DIFF_INPUTS)
 		return dev_err_probe(dev, -EINVAL,
-				     "Invalid diffreential channel %u\n", pin);
+				     "Invalid differential channel %u\n", pin);
 
 	if (pin >= AD4130_MAX_ANALOG_PINS)
 		return 0;