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'.

[*] Documentation/devicetree/bindings/power_supply/lp8727_charger.txt

Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Milo Kim <milo.kim@ti.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>