power:lp8727_charger: parsing child node after getting debounce-ms
According to lp8727 bindings[*], charging parameter is optional.
So parsing can be skipped in case those properties are undefined.
However, 'debounce-ms' should be read prior to checking the properties.
Otherwise, 'debounce-ms' property will be ignored even it is configured
inside the DT.
So, counting child is processed after updating 'debounce-ms'.