regulator: wm8400-regulator: Repair dodgy kerneldoc header formatting

W=1 kernel builds report a lack of descriptions for various
function arguments.  In reality they are documented, but the
formatting was not as expected '@.*:'.  Instead, some weird
arg identifiers were used.

This change fixes the following warnings:

 drivers/regulator/wm8400-regulator.c:243: warning: Function parameter or member 'dev' not described in 'wm8400_register_regulator'
 drivers/regulator/wm8400-regulator.c:243: warning: Function parameter or member 'reg' not described in 'wm8400_register_regulator'
 drivers/regulator/wm8400-regulator.c:243: warning: Function parameter or member 'initdata' not described in 'wm8400_register_regulator'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Cc: patches@opensource.cirrus.com
Link: https://lore.kernel.org/r/20200626065738.93412-9-lee.jones@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/wm8400-regulator.c

@@ -234,9 +234,9 @@ static struct platform_driver wm8400_regulator_driver = {
  * the regulator API.  It is intended to be called from the
  * platform_init() callback of the WM8400 MFD driver.
  *
- * @param dev      The WM8400 device to operate on.
- * @param reg      The regulator to control.
- * @param initdata Regulator initdata for the regulator.
+ * @dev:      The WM8400 device to operate on.
+ * @reg:      The regulator to control.
+ * @initdata: Regulator initdata for the regulator.
  */
 int wm8400_register_regulator(struct device *dev, int reg,
 			      struct regulator_init_data *initdata)