qcacld-3.0: Refine the "set scan oui" logic

Make the following updates to the "set scan oui" logic:
1) Exclusively use the Unified WMI data structures.
2) Update the HDD<=>SME interface to enforce the contract that SME
   must not make any assumptions about the buffers provided by HDD.
3) Replace instances of mixed-case identifiers.
4) Document the API definitions, not the implementations.

Change-Id: I5df3962fc45395b37b4e566f98b840e37f601d26
CRs-Fixed: 2389640
6 files changed