qcacmn: Configure burst duration as 0 when NDP is active

Currently, burst duration is configured as 240ms when NDI has
active NDPs. Firmware can go off-channel for scanning for this
duration which blocks data transfer. But some NDP based
applications(e.g. audio transfer) can tolerate a latency of
a maximum 120ms. So firmware can't go off-channel for
more than 120ms.
Configure burst duration as 0 when an NDP is active
to make sure firmware does non-burst scan and returns to NDP
channel within 120ms after scanning.

Change-Id: I33ca3a9d11c54b1173a3abd3ed7aa19c9c5662e5
CRs-Fixed: 2679038