regulator: of_regulator: Add missing colon for rdev kerneldoc argument

Kerneldoc validation gets confused if syntax isn't "@.*: ".

Adding the missing colons squashes the following W=1 warnings:
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Cc: Rajendra Nayak <rnayak@ti.com>
Link: https://lore.kernel.org/r/20200708124832.3441649-3-lee.jones@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/of_regulator.c

@@ -532,7 +532,7 @@ static bool of_coupling_find_node(struct device_node *src,
 /**
  * of_check_coupling_data - Parse rdev's coupling properties and check data
  *			    consistency
- * @rdev - pointer to regulator_dev whose data is checked
+ * @rdev: pointer to regulator_dev whose data is checked
  *
  * Function checks if all the following conditions are met:
  * - rdev's max_spread is greater than 0