qcacld-3.0: sme: Replace explicit comparison to NULL

Per the Linux Kernel coding style, as enforced by the kernel
checkpatch script, pointers should not be explicitly compared to
NULL. Therefore within sme replace any such comparisons with logical
operations performed on the pointer itself.

Change-Id: I26dc90bbae78329dd04768a21c63a9ea55c8fdb4
CRs-Fixed: 2418388
12 files changed