power: supply: charger-manager: Collect all power_supply_changed() calls

Current charger-manager calls power_supply_changed() whenever charging
status is changed. Remove the separated power_supply_changed() calls
and let it be called at end of try_charger_enable() function which
is called to set charging/discharging.

Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>