iio: gyro: adis16080: Fix formatting issue

Kerneldoc expects attributes/parameters to be in '@*.: ' format.

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

 drivers/iio/gyro/adis16080.c:49: warning: Function parameter or member 'lock' not described in 'adis16080_state'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Cc: Michael Hennerich <Michael.Hennerich@analog.com>
Cc: Barry Song <21cnbao@gmail.com>
Link: https://lore.kernel.org/r/20200716135928.1456727-13-lee.jones@linaro.org


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