MLK-12928-21 power: pf1550: fix charger interrupt never caught

MLK-12928-21 power: pf1550: fix charger interrupt never caught

Charger interrupt can't be caught anymore after plug in DC 5V in/out dozens of
times, that caused by VBUS_I or CHG_I pending interrupt not cleared in time. The root
cause is VBUS_I and CHG_I will be triggered in very narrow window, and VBUS_I/CHG_I
act as the sub-interrupt of charger and share the same interrupt handler. Thus if CHG_I
interrupt status is coming while VBUS_I handler is running, CHG_I interrupt status will
never be cleared, since interrupt has been disabled in ISR. The unclear CHG_I interrupt
status make pf1550 never trigger next interrupt again. So clear all charger interrupt
status in ISR to workaround instead of ack for every sub-intterrupt.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>