iio: adc: rzg2l_adc: Remove unnecessary channel check from rzg2l_adc_read_label()

Remove unnecessary channel check from rzg2l_adc_read_label(), as the
channel error handling is already done in probe(). Therefore no need to
validate at runtime.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20220515060337.16513-3-biju.das.jz@bp.renesas.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/rzg2l_adc.c

@@ -260,9 +260,6 @@ static int rzg2l_adc_read_label(struct iio_dev *iio_dev,
 				const struct iio_chan_spec *chan,
 				char *label)
 {
-	if (chan->channel >= RZG2L_ADC_MAX_CHANNELS)
-		return -EINVAL;
-
 	return sysfs_emit(label, "%s\n", rzg2l_adc_channel_name[chan->channel]);
 }