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

drivers/iio/gyro/adis16080.c

@@ -38,7 +38,7 @@ struct adis16080_chip_info {
  * @us:			actual spi_device to write data
  * @info:		chip specific parameters
  * @buf:		transmit or receive buffer
- * @lock		lock to protect buffer during reads
+ * @lock:		lock to protect buffer during reads
  **/
 struct adis16080_state {
 	struct spi_device		*us;