wlan: Fix possible null pointer dereference in WDA_IsSelfSTA

In function WDA_IsSelfSTA(), pointer pWDA will be NULL
dereferenced if VOS_GET_WDA_CTXT() returns NULL.
Added NULL pointer check before accessing the pointer.

Change-Id: I40dcac790d0bc76939c13b4af864139889403a02
CRs-Fixed: 679406.
wlan: check for pAdapter NULL dereference.

this fix will ensure NULL pointer derefernce
in function hdd_deinit_batch_scan.

Change-Id: I0877dde6fff3534477c4a866a91607561b61d33c
CRs-Fixed: 621421
wlan: Clean up WD thread to avoid crash.

In function VosWDThread() we check if resetinprogress
is set in WD context but still execute WLAN re-init
which causes system to crash.
Clean up WD thread so that it doesnot execute WLAN
re-init when it is not shutdown.

Change-Id: Ica0ab74e98f2153dcab91e9aa111bc6dacc6e9ba
CRs-Fixed: 682616