qcacmn: Refine struct wmi_unified_pmk_cache (phase 1)

The current definition of struct wmi_unified_pmk_cache has the
following anomalies:
1) It contains an unnecessary tlv_header field. Only the fw-api
   structs should contain TLV headers.
2) It contains a mis-named session_id field. Common structures should
   use converged terminology, in this case vdev_id

To fix the first issue just remove the tlv_header field since it isn't
used.  To fix the second issue takes a phased approach. For phase 1
replace the session_id field with an anonymous union which contains
both the existing session_id field and a new vdev_id field. Being part
of a union these field will overlay each other.

Subsequent phases will replace session_id references with vdev_id
references, and then remove the union, leaving just the vdev_id field.

Change-Id: If4be27111c604c16ea437aa654210cdff28220a7
CRs-Fixed: 2363430
1 file changed