iio: adc: max9611: Demote obvious misuse of kerneldoc to standard comment blocks

No attempt has been made to document any of the demoted structs here.

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

 drivers/iio/adc/max9611.c:117: warning: cannot understand function prototype: 'const unsigned int max9611_mux_conf[][2] = '
 drivers/iio/adc/max9611.c:145: warning: cannot understand function prototype: 'const unsigned int max9611_gain_conf[][2] = '

Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/max9611.c

@@ -110,7 +110,7 @@ enum max9611_conf_ids {
 	CONF_TEMP,
 };
 
-/**
+/*
  * max9611_mux_conf - associate ADC mux configuration with register address
  *		      where data shall be read from
  */
@@ -133,7 +133,7 @@ enum max9611_csa_gain_params {
 	CSA_GAIN_OFFS_RAW,
 };
 
-/**
+/*
  * max9611_csa_gain_conf - associate gain multiplier with LSB and
  *			   offset values.
  *