iio: adc: palmas_gpadc: Drop duplicated the in comment.

In line 460 of the palmas_gpadc.c file, fix kernel comment errors.

Signed-off-by: Andy Shen Shen <shengaoya@inspur.com>
Link: https://lore.kernel.org/r/20230921031444.63594-1-shengaoya@inspur.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>