regulator: sy7636a: fix lifecycle of power good gpio

Attach the power good gpio to the regulator device devres instead of the
parent device to fix problems if probe is run multiple times
(rmmod/insmod or some deferral).

Fixes: 8c485bed ("regulator: sy7636a: Initial commit")
Signed-off-by: Andreas Kemnade <akemnade@kernel.org>
Reviewed-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Message-ID: <20250906-sy7636-rsrc-v1-2-e2886a9763a7@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>