qcacld-3.0: Replace typedef tSirWifiIfaceStat

The Linux Coding Style enumerates a few special cases where typedefs
are useful, but stresses "NEVER EVER use a typedef unless you can
clearly match one of those rules." The tSirWifiIfaceStat typedef does
not meet any of those criteria, so replace it (and the "tp" variant)
with a properly named struct.

Change-Id: I70f0e8c038d061cb201b52ce07097c68bcb93346
CRs-Fixed: 2428989
4 files changed