While requesting sta stats, tx/rx netdev stats update are
happening from adapter. But as part of latest code change
these stats are moved from adapter to dp interface, because
of which some of stats values are displayed as 0.
To Fix the issue get tx/rx netdev stats from dp interface,
Also add calls to clear netdev stats
Change-Id: I64523b035c1d902ccc4a45d82f7508751e518150
CRs-Fixed: 3247540