regulator: doc: remove documentation comment for regulator_init

Remove documentation comment related to regulator_init callback.
This solves the following warning when building the kernel documentation:

./include/linux/regulator/machine.h:290: warning: Excess struct member 'regulator_init' description in 'regulator_init_data'

Fixes: 602ff58 ("regulator: core: remove machine init callback from config")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/lkml/20241023155257.0fa7211d@canb.auug.org.au/
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://patch.msgid.link/20241023-regulator-doc-fixup-v1-2-ec018742ad73@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

include/linux/regulator/machine.h

@@ -273,8 +273,6 @@ struct regulator_consumer_supply {
  *               be usable.
  * @num_consumer_supplies: Number of consumer device supplies.
  * @consumer_supplies: Consumer device supply configuration.
- *
- * @regulator_init: Callback invoked when the regulator has been registered.
  * @driver_data: Data passed to regulator_init.
  */
 struct regulator_init_data {