qcom-charger: update parallel charging states after boot

If a USB charger is already attached before the master charger
probes, the master will miss updating parallel charging states.

ICL and charge state change interrupts get triggered before
their handlers are registered. Hence these interrupts will not
be handled.  Obtain the state of missing interrupts by polling
status registers.

If parallel charging is ready on master side before the parallel
charger probes, then parallel charging will not be enabled.
Check if parallel charging is ready once the parallel charger
probes so parallel charging can be enabled immediately.

CRs-Fixed: 1033688
Change-Id: Ic91baeaeb7410b6f265b8bfa8e31e2bcff8dfce2
Signed-off-by: Harry Yang <harryy@codeaurora.org>