Deal with the charger type changing without a vbus-disconnect being
reported in between the 2 charger type states:

-Do not return from axp288_charger_extcon_evt_worker early in this case
 (track old_chg_type)
-Make calling axp288_charger_enable_charger with the same value as before
 a nop, to avoid the need for the caller to check this
-Do no do a dev_err when axp288_charger_enable_charger returns an error,
 axp288_charger_enable_charger already returns an error itself
-Disable the charger before changing the charge-current setting (nop if
 vbus was seen as disconnected before the change)
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>