iio: adc: max1363: Fix kerneldoc attribute formatting for 'lock'

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

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

 drivers/iio/adc/max1363.c:190: warning: Function parameter or member 'lock' not described in 'max1363_state'

Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Rohit Sarkar <rohitsarkar5398@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/max1363.c

@@ -150,7 +150,7 @@ struct max1363_chip_info {
  * @current_mode:	the scan mode of this chip
  * @requestedmask:	a valid requested set of channels
  * @reg:		supply regulator
- * @lock		lock to ensure state is consistent
+ * @lock:		lock to ensure state is consistent
  * @monitor_on:		whether monitor mode is enabled
  * @monitor_speed:	parameter corresponding to device monitor speed setting
  * @mask_high:		bitmask for enabled high thresholds