Fix the issue with active probe request packet  on DFS channel

Revert the DFS channel scan type to passive when AP sends the
channel switch indication.

Change-Id: Ib5049ca744e58720cd07268dcd6bc8b295767489
CRs-Fixed: 522420
wlan: Fix RX low resource recovery mechanism

RX low resource recovery callback registered
with PAL should not be initialized to NULL
every time a packet is being allocated.
This can lead to unrecoverable DXE state when
the packet allocation funtion is preempted by
the low resouce recovery mechanism which checks
for DXE callback and returns without cleaning the
DXE state.

CRs-Fixed: 529193
Change-Id: Ie1c02b265bf6e870d4a3f5ec508e7af9124f95a6
wlan: Revision 3.2.3.164

Revision 3.2.3.164