regulator: core: Release coupled_rdevs on regulator_init_coupling() error

This patch fixes memory leak which should happen if regulator's coupling
fails to initialize.

Fixes: d8ca7d18 ("regulator: core: Introduce API for regulators coupling customization")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20191025002240.25288-1-digetx@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -5198,6 +5198,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	regulator_remove_coupling(rdev);
 	mutex_unlock(&regulator_list_mutex);
 wash:
+	kfree(rdev->coupling_desc.coupled_rdevs);
 	kfree(rdev->constraints);
 	mutex_lock(&regulator_list_mutex);
 	regulator_ena_gpio_free(rdev);