qcacmn: Update Peer rx/tx rate based on DATA packets

Packets sent/received at fixed rate were also considered to
update the client rates as displayed in wlanconfig command output.
An idle client transmits NULL packets at basic rate and hence
rx rate shows up the basic rate when an idle client is connected.
Consider only data packets to update rates. Do not consider
NULL packets for rate update.
CRs-Fixed: 2435447

Change-Id: Icbf9f2a656bb0d36e16d953952c529185c119f17
3 files changed