hwmon: (hih6130) Fix documentation of struct hih6130

Sparse reports:

drivers/hwmon/hih6130.c:56: warning:
	No description found for parameter 'client'
drivers/hwmon/hih6130.c:56: warning:
	Excess struct member 'hwmon_dev' description in 'hih6130'

Signed-off-by: Guenter Roeck <linux@roeck-us.net>