power: qpnp-charger: check if dc is present after probe

If a DC charger is connected during bootup the dcin_valid
interrupt does not trigger after requesting the interrupt.

Fix this by calling the DCIN_VALID interrupt handler
at the end of the charger probe to read the real time
interrupt status bit and take appropriate actions.

CRs-Fixed: 491426
Change-Id: I5dfcc4542a28c4375a5f12acad44207c0ffa237a
Signed-off-by: David Keitel <dkeitel@codeaurora.org>