dt-bindings: hwmon/pmbus: ti,lm25066: document regulators

All devices documented in the lm25066 binding are intended for use with
a regulator, be that for purely monitoring purposes (lm25056) or, for
the other devices, as the controller of that regulator. The binding does
not currently allow regulator child nodes, so add one.

Each of these devices interacts with only a single regulator and
documentation refers to it as "Vout", hence the choice of child node
name.

Acked-by: Zev Weiss <zev@bewilderbeest.net>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240223-tingling-mutt-dd55dd87ff5e@spud


Signed-off-by: Guenter Roeck <linux@roeck-us.net>