regulator: fix OF node imbalance on reuse

regulator: fix OF node imbalance on reuse

Johan Hovold <johan@kernel.org> says:

These drivers reuse the OF node of their parent multi-function device
but fail to take another reference to balance the one dropped by the
platform bus code when unbinding the MFD and deregistering the child
devices.

Fix this by using the intended helper for reusing OF nodes.

Note that the first two patches will cause a trivial conflict with Doug's
series adding accessor functions for struct device flags which has now been
merged to the driver-core tree:

	https://lore.kernel.org/r/20260406232444.3117516-1-dianders@chromium.org

Link: https://patch.msgid.link/20260408073055.5183-1-johan@kernel.org