power: qpnp-smbcharger: limit enabling parallel charger frequently

Currently, whenever the charger driver receives an AICL done interrupt,
it will go and attempt to enable parallel charging if it's available.
However, this can create a loop where a charger cannot support parallel
charging with load, but upon disabling parallel charging, the AICL done
interrupt from the AICL tries to re-enable parallel charging.

Fix this by not allowing parallel charging to be re-enabled more than
once every 30 seconds.

CRs-Fixed: 815311
Change-Id: Id8f9aea3f3eefda4b50d3807f666bb11377b229e
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>