[qca-nss-drv] PPPoE code clean-up.

*Use the reworked PPPoE API. The previous API was implemented in the wrong place.
The new API is now in the pppoe.c file and implemented
in a smarter way.
* Move the PPPoE stats handling from driver to ECM.

Change-Id: Ib2edd069e13b85d885221cc7c4043fdc68e3705e
Signed-off-by: Murat Sezgin <msezgin@codeaurora.org>
3 files changed