power: qpnp-smbcharger: re-arrange parallel charger detection check

In scenarios where fast-charge/taper interrupt fires even before
src_detect_handler detects the parallel charger, parallel charging
will remain disabled. Fix this by adding a parallel charger detection
check in fastcharge and taper handler.

CRs-Fixed: 984187
Change-Id: I082cad6cf1bc3e8d9a5c327222f72d046190f9ca
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>