wlan: Remove roam preauth command on disconnect indication

Roam preauth command is queued and before processing the
preauth, exit_bmps command is processed to put device into
full power. The sSirBssDescription pointer from the roamable
AP list is assigned to pLastRoamBss field in the preauth
roam command queued. Deauth frame is received from AP and
disconnect indication is sent to SME. As part of this,
roamable AP list containing bss description is purged which
can cause kernel panic due to use after free of AP bss
decription as part of processing preauth command.

Fix is to remove preauth command on disconnect indication
from lim.

Change-Id: I50e99af852eaf9b15b9f1a1075aaeb1e39a9dbfb
CRs-Fixed: 2345682