iio: adc: rockchip_saradc: Demote seemingly unintentional kerneldoc header

This is the only use of kerneldoc in the source file and no
descriptions are provided.

Fixes the following W=1 kernel build warning(s):

 drivers/iio/adc/rockchip_saradc.c:190: warning: Function parameter or member 'reset' not described in 'rockchip_saradc_reset_controller'

Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/rockchip_saradc.c

@@ -207,7 +207,7 @@ static const struct of_device_id rockchip_saradc_match[] = {
 };
 MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
 
-/**
+/*
  * Reset SARADC Controller.
  */
 static void rockchip_saradc_reset_controller(struct reset_control *reset)